I'm expecting a topic like this to have already been made. But I think it's a fun topic - well, in a way - so I'll bring it back. This isn't a revival, just an update. And I'm trying to add to the activeness of the forum, too.
So just post your favourite/least favourite pokemon here. You can add to your post any time at all.

[Me]
Best:
Mudkip x Evolutions
Mightyena x Poochyena
Bagon [...]
Absol
Piplup x Evolutions
Worst:
Eevee
Mew
Chikorita
Celebi
Manaphy
Phione
Shaymin
Jirachi
Plusle [sorry, Zeph!]
Minun
Pikachu
Pichu
Lugia [not much, but still overrated]
Espeon
Ralts

Hmm...
My absolute favorite is Sneasle and Weavile, but I seem to get to like pokemon as I decide to raise them in my game. Like, now I love froslass simply becuz I raised an awezum one in my pearl game. ^^
And I do not like... Bronzongs. XP

Hmm...

{Best}

Sneasel and Vulpix pwn all. *walks off* XD

{Worst}

Bronzor
Bronzong
Bidoof
Bibarel

*murders them all* I can never beat those stupid Bronzors with my Prinplup! *spazzes* ><

Favs:
Charizard <33
Umbreon <3

Extremely Disliked:
Bronzor
Bronzong

I hate those two!! DDx And Maple, I guess we have the same worst favs. xD

Omaigad.

. B E S T .
Arceus
Mudkip
Charizard
Umbreon
Houndoom
Suicune
Luxray
Pikachu
Lugia
Ho-Oh
Latias
Articuno
Grovyle
Blaziken
Eevee's all evolutions
Mew
Poochyena
Salamence
BIDOOF
*And the list goes on*

. L A M E .
Nosepasses another evolution D: Can't remember name,
Bronzong
Smoochum + Jynx
Mr. Mime

~ B E S T~
Houndoom, Quilava, Pikachu, Buizel, Sneasel and Weavile, Riolu, Lucario, Butterfree, Meowth, Persian, Mighteyena, Charmander & evolutions, Eevee and evolutions, Kangaskhan, Pidgeotto, Cressila, Tyranitar, Milotic, Amphoros, Zangoose, Ninetales, Vulpix, Miltank, Suicune, Entei, Raikou, Mew, Mewtwo, Palkia, Flygon, Salamance, Dragonite, Garchomp, Buizel, Floatzel, Blazekin, Grovyle, Swellow, Pichu, Raichu, Bulbasaur, Chikorita, Cyndaquil, Typhlosion, Totodile, Squirtle, Piplup, Chimchar, and it goes on and on and on and on...

~ W O R S T~
The same as everybody else: Bronzor and Bronzong. Oh, and JYNX! That creepy, ugly little...

Best:
Charmander
Charmeleon
CHARIZARD!!! (of course) ::D:
Cyndaquil
Quilava
Typhlosion
to shorten the list: all fire pokemon
and Luxray
ooh, ooh, ooh. MAGIKARP!!! *yays for the stupid fish pokemon!!* :B):

Worst:
Bronzong
most other 'B' pokemon
and basically all the new Sinnoh PKMN,

no offence but Kanto and Johto were the best, Hoenn close but Sinnoh just didn't stack up in my book. :unsure:

Rare pokemon are overrated... likes them but doesn't like them... it's a complicated emotion. ::(:

The best is Mewtwo. He's powerful, cool, and I can relate to him.

The worst is Ditto. The breeding center thing creeps me out..

Well (we can write multiple Pokemons 0_o) the best Pokemons for me are Bagon, Oddish, Hoppip, Vulpix, Spheal, Corsola, Cherubi and all of their evolution line. The worst IS....... a Pokemon that should never existed in the history of Pokemon World.....

Arceus which is FTL