So, I LOVE book series. There's anticipation for what's going to happen in the next book, and you get to be interested in them longer than when there's a just... a book.
So, here's where you can talk about what kind of series you like and which ones in particular you are interested in.
Whenever someone asks me what my favorite book is, I always refer to a series rather than a single book.
Most of the books I like are fantasy, science fiction, or adventure stories. Here's a list of my favorites (in order =P):
Pendragon
Alex Rider
Uglies/Pretties/Specials/Extras
Five Ancestors
The City of Ember

I would advise anyone to read these books if they haven't already. I'm pretty sure most if not all of you would like uglies/pretties/specials/extras. It's probably the most popular series in my school. Pendragon is a fantasy adventure- I really get to think about it and make up stories in my head and predict what will happen and such. Alex Rider is about a teenage spy- an adventure story for people who like very fast-paced books. Five Ancestors are pretty short, usually only a little over 200 pages, and they're generally fast but action-packed reads. The City of Ember... hmm... I haven't read them in a while because a new book hasn't come out in a long time- but will later this year, as well as a movie of the first book (The City of Ember). There is also a movie of the first alex rider book (Stormbreaker).

Aw man i used to loooove series but now I'm mostly into single books and stuff

My very favorites used to be Warriors, Guardians of Ga'hoole, Redwall, and the Chronicles of Narnia.
In Warriors, I read up to the eigth book and half of the ninth book and then I just....stopped. Same with Ga'hoole, I read up to the Legends of Ga'hoole and stopped. With Redwall I started the second book and was like tl;dr. I still have this huge Narnia book with all the books in it. I read about four of them. Yup.

Not in any particular order, (except for the order I remembered them in) except for the first one, which is my fav as far as I can remember. So the rest will be numbered for my love for them, 10 being the best and 1 the worst.

Heir Apparent (<33333 10 billion~)
Uglies/Pretties/Specials/Extras (9.9)
Lightning Thief/Sea of Monsters/Titan's Curse (8.5)
Redwall (7)
Warriors (7)
Queen of Second Place/ Queen B (8.5)
Fruits Basket (even though it's a manga.. it still should count, right?) (9.9)
Heir of Mistmantle (7)

I KNOW I'm missing lots, but I can't seem to think of them. ^^; I'll edit if I think of some more.

YES! BOOKS! ROOOOAAAR

I liked Pendragon and Alex Rider, and heard that Uglies and stuff was good, but never got around to reading it. I did read some of Redwall and Warriors, but so long ago that I only remember that they were about talking animals and cats, respectively.

However, my favorite series of all time...

The Wheel of Time(Robert Jordan) (10)

The Sword of Truth(Terry Goodkind) (9.9)

The Dark Tower(Stephen King) (9.8)

These are the best series EVER. I hate to rank them, but if I had to choose, that's how it would go.

Oh, and I'm really sad because the author of the Wheel of Time, Robert Jordan, died before the final twelfth book was published. So they're getting some replacement author to do it, but I know it just won't be the same... =(

Yeah. By the way, go read the Wheel of Time. Now. It should take at least a week. If you like that, go on to SoT and TDT :D

O__O there's nothing I can't finish in at most 3 days. So, if that's a challenge I betcha I could.. =P How many pages?

Ooh! Books! =D Prepare for a long, long post.

The Abhorsen Trilogy by Garth Nix is definitely my all-time favorite series ever. <3 Garth Nix creates incredibly believable fantasy worlds, and I absolutely love the concepts of Charter magic and Free Magic. Seriously, these books are amazing. The description of the nine gates of Death and the seven necromancer's bells add so much to the different aspects of the story, and I could go on forever. <3 One of the most original things I've ever read.

Following in a close second is the Midnighters trilogy by Scott Westerfeld. A lot of you mentioned Uglies; this is by the same author. The secret hour and the Midnighter's powers are fascinating to me, and I like seeing the story from all of the Midnighter's points of view, not just one character. The characters in this story, and the excellent descriptions and unique concepts, definitely drag me into this series. ^^

I'm also a fan of the Uglies and Keys to the Kingdom series, by Scott Westerfeld and Garth Nix, respectively. As a side note, Garth Nix is by far my favorite author. <3

The Pendragon series by DJ MacHale and the Inkheart trilogy by Cornelia Funke are also some of my favorites, but as of now I'm a little detached from them, since it's taking a while for the next books to come out, and I don't have time to go back and reread them.

And now I'm getting tired of typing out paragraphs for all of my favorites, so here's the rest in a list. xD The Warriors series by Erin Hunter; Guardians of Ga'hoole by Kathryn Lasky. The Fire Within series by Chris D'Lacey; the OutCast series by Christopher Golden and Thomas E. Sniegoski. The Silverwing trilogy by Kenneth Oppel. The Divide trilogy by Elizabeth Kay. And the Inheritance trilogy by Christopher Paolini. Oh, and of course Harry Potter. ^^

And since I can't finish this post without including my stand-alone favorites...

Searching for David's Heart by Cherie Bennett and The Power of Un by Nancy Etchemendy are both favorites of mine because of how powerful and moving they are. They're both written in first person, and that's probably what's helping to draw me in. If you're looking for something moving, go for one of these.

Such is the case with The White Darkness by Geraldine McCaughrean is definitely an interesting read. Also written in first person and also pretty powerful, it's about a girl who's in love with someone who died 90 years ago. (He's like an imaginary friend to her.) It's very, very interesting. =D

Oh, I could go on forever...

I'd have to say those books by my two favourite authors:

• Peeps/The Last Days by Scott Westerfeld
• The Midnighters Series by Scott Westerfeld
• The Abhorsen Trilogy by Garth Nix
• Keys to the Kingdom Series by Garth Nix

I didn't put the Uglies series there. They were great, but by the time I'd reached Specials I couldn't even be bothered finishing it. About halfway through it I couldn't be stuffed reading over and over about how the Specials had superior eyesight and crap like that. Although Scott Westerfeld is still my favourite author. As always. And Garth Nix is a close second as always. Nice to find so many Westerfeld/Nix fans in the same place!

And I used to live near Garth Nix! I never saw him, but his author's biography somewhere (maybe in one of his books; I think Shade's Children) said where he lived. I knew it was in the same city (Melbourne) but not a nearby suburb. I'm still dying to meet both authors.

There's more series that I like, but if I name one I'd have to name others. And there's this really good one that's almost as good as Peeps/The Last Days that I can't remember.

Now to reply to all this. xD

Warrior People- I started reading one of the newer books once, but I have a bad habit of not finishing some books that I start (or at least I used to).

Pointy- Most of those books are too old for me. XP I really like modern things.

Hazelnut- I haven't heard of a lot of those, but I'm sure they're good. =3

Avielus- I haven't heard of any that you said, and I'll consider reading them. And I'm glad you like alex rider and pendragon. =D You should give the Uglies series a try. They're some of the best books I ever read.

Shadow- What is The Divide about? I saw a book or two from it at the library once but I was looking for a pendragon book at the time so I didn't stay to look. =P I've heard of the midnighters- I might read them sometime. =P I'm glad you like Uglies and Pendragon. ^^ There's going to be a movie of Inkheart, so I thought it might be good and so I was thinking about reading it sometimes because also, some of my friends like it.

Harry Potter- I don't know why I'm not interested in them. I read most of the first book and liked it, but I just kinda stopped. The book was good, but I guess there too... well, popular for me. I guess I like to cheer for the underdog books. xD

October- About Peeps/The Last Days, does the last days come before or after peeps or are they different series? I have peeps on my bookshelf in my room, but I haven't gotten around to reading it. =P

@Hazelnut: Well, each book is about 700+ pages... and there are 11 books. So... good luck. Tell me what you think about it XD

I notice a lot of you have read Midnighters. So have I. It's goood. =D

I have read The Divide trilogy also... it was pretty good.

I have the Abhorsen trilogy... because it is godly like that.

I actually didn't like Inkheart that much(it was a little dull for me), but I think a movie of it would be ...interesting, at least.

Also, has anybody read A Song of Ice and Fire? I started that series, but can't seem to get my hands on the second book.

They're both in the same series. Peeps comes first, The Last Days comes second. Mind you, the start of The Last Days has many musical terms in it and is a bit repetitive. Don't let it put you off though, it's almost as good as Peeps.

I liek books. :D So I'm into multiple series... hm, what have I been reading as of late? These are in no particular order... or maybe they are?

Books by Tamora Pierce are collectively one of my favourites. She's written about twenty-five or so, generally separated into quartets. (I've read 'em all, heh. :P) She's gotten so much better since her earlier works. xD; (to those who don't know, they're a sort of mideval fantasy.)

The Abhorsen Trilogy (see, Shadow?) and the Keys to the Kingdom Series by Garth Nix are definitely up there. His writing style is so interesting in the way that he creates such unnatural universes and makes them seem plausible. A delightful read. I've only read up to Thursday in Keys to the Kingdom, but I've finished Abhorsen (save for the short stories in Over The Wall).

The Tiffany Aching series by Terry Pratchett are impossible not to love. <3 He has a hilarious wit and an amazing knack for storytelling. I want to read some of his adult books some time.

Harry Potter is awesome, no denying it. I'm not a huge potterfan, but be assured I was one of the people who stayed up until 3 in the morning to get Deathly Hallows.

...I can't believe nobody's mentioned the Twilight series by Stephenie Meyer. What? Blank out or something? My conscience tells me I shouldn't like them because they're vampire romance books, but my heart has my conscience bound and gagged in a corner, so I love them. <3

I haven't read the rest of the series, but Ender's Game was simply amazing, and I still think about it.

...Now, I could also rant about series that I don't like, such as maybe Maximum Ride, or series that I used to like but have long since gone stale, such as Warriors and Ga'Hoole, but I don't want to spread negativity to this topic. C:

I've read the first one for school, and it was good, so maybe I'll read the rest of the series sometime...

Yeah.. Warriors has gone a bit stale. =/ I like the role-plays, but I only respect the books for how much I used to like them. Same with Redwall, but that's only because Brian Jacques hasn't writing the next book yet, and it's driving me nuts. I'm sure once it comes out I'll get back into it.

I was going to say Ender's Game myself, but I haven't read any of the sequels, so I can't really judge the whole series - that was a terrific read - absolutely amazing. And I've read a quarter of the Tamora Pierce books. I remember reading it and then having to read something for school and never getting back to it. I've wanted to read those for ages, though. I've slowly forgotten about them.

Yes! Ender's Game! Actually, if you really liked that, you should go and read Orson Scott Card's other series, Tales of Alvin Maker and ...Homecoming I think it's called? (I don't know the series name, but I read all the books in it... sad)

Tamora Pierce... did she write the Circle of Magic books? With Briar, Daja, Sandry, and Tris? Because those books pwned. Hard.

Harry Potter!

I'm not really that much of a book reader - at least not at the moment - though I do like books. >.<; My favourite series are probably Harry Potter and Warriors. The Harry Potter books were just a joy to read through, really suspenseful and intriguing (though I haven't actually read the seventh book yet :D;), and I adore cats, so I find the Warriors series wonderful and very interesting. I find the idea of cats living in organised clans in the wild really cool.

I haven't read past Starlight yet, but I am planning to eventually. ^^; I sort of read Dawn in not quite the right page order, and did the same with Starlight. A friend gave me Firestar's Quest as a gift quite a while ago, and I've had a look at that, but I haven't read much of it yet.

There are a few book series I read a while ago that I liked, but I wouldn't count them as favourites - I saw that Zephyr mentioned Tamora Pierce, and that reminded me of the two of her book series that I've read; the Song of the Lioness series, and the Protector of the Small series. I also liked most of a series called Stravaganza by Mary Hoffman.

I read a lot of series (well, I read a lot of books in general), although I forget most of the author's names.

The Inkheart trilogy is one of the best series I have read in a while. The third one isn't out yet* (should be by the end of the year, though), but the other two are awesome by themselves.

The Warriors series is okay, but it got worse in the second series and is slowly recovering. I swear, on every page of Twilight it said something about Squirrelflight hating Brambleclaw or vise versa (and of course they got together in the end).

Guardians of Ga'hoole isn't a very good series at all and I don't know wy everyong likes it so much. I mean, it was good at first, but then everyone grew up and become perfect. They do nothing wrong. I don't like it as much as I used to.

Has anyone read the Xanth series? It's a fantasy series my friend and I read mainly intended for adults (I think; it's sort of hard to tell), and it has so many puns in it. I'd describe them to you, but they're just too horrible (they give me nightmares ((sort of))).

My other friend has the Twilight series. She says she's going to make me read it one of these days. They say it's good, but I'm not sure.

Atherton is a very awesome series. The characters and plot are believable, plus it's my favorite kind of science fiction– it's set in a place that isn't a planet, but something else (like Ringworld, sort of).

There must be some that I'm forgetting, but these are all I can remember at this moment.

*it is in Germany, though. I have it in German and if I don't learn German and read it before it comes out in English I am going to feel very silly. Well, if I don't, at least I ca read this trilogy about Venice that has the first book translated and none of the others.

Aggh, how long can it possibly take for Inkdeath to come out? >O I try not to think about how long it seems to be taking, but every time I do it seems like it's taking forever... and ever...

The Guardians of Ga'hoole series was best in the beginning, I agree, but since then I've just been hooked. xD I still like it, although there's a lot more in the newer books that I don't like... but there's only one book left to come out, so I might as well complete my collection. =3

I've also started reading the Shadow Children series by Margarete Peter Haddix. I think it's by her. I just finished Among the Imposters, and I really like the series. ^^ It has a really cool plot, just enough stuff to keep you interested and wondering, but no more than what's needed, keeping it light and easy to read. =D It's nice as a sort of relaxing reading type thing. If that makes sense.