Stolen from Beccalicious. XD

So yeah. Starting from Upper-left, going right.
Milotic - Probably my favorite, but it's a bitch to catch its pre-evolved form then using the poke-blocks to make it evolve into this. Yeah, it's a giant snake-like water thing, but supposedly it's supposed to be the most beautiful of all pokemon. I think it looks pretty awesome and kicks ass in the game.
Dusclops - Nothing can One-Hit-KO this thing. Nothing. XD
Houndoom - Yes, a Hellhound. What more can I say?
2nd Row
Blissey - Big pink blob of fluff that has....the highest HP in the game. Plus its fun to beat other trainers with it.
Steelix - No explanation. Steelix = Win.
Altaria - The underdog of Dragon-types, but pretty fun to use. Reminded me of Sexy-no-Jutsu. XD