Bug: Heracross and Venipede/Scolipede. I can't decide between the two!
Dark: Tyranitar!!!
Dragon: How the hell am I supposed to decide?! Hydreigon has such a cool design and typing, but Flygon, Dragonite, Noivern, and that cutie Goomy...
Electric: Rotom
Fairy: Togekiss
Fighting: Breloom, though I also love Medicham for his typing!
Fire: Volcarona
Flying: Talonflame
Ghost: Gengar, Gengar, Gengar!!!
Grass: Ferrothorn. How did I ever get by without one in White?!
Ground: Mamoswine
Ice: Jynx
Normal: Girafarig, but also Tauros, Porygon/2/Z and Snorlax.
Poison: Ekans/Arbok. No, I like Muk even more!!!
Psychic: Latias
Rock: Tyrantrum
Steel: Metagross
Water: There are just too many to choose from! Lanturn, Kingdra, Greninja, Gyarados, Lapras, Poliwrath, Politoed, Suicune!