Ah, I'll probably end up forgetting a ton of my favorite ones, but oh well, lol. *goes off to flip through her Pokemon book* Let's see...
Fire: I'll have to go with Charmander; It's so cute! But I also love Vulpix, Flareon, Ponyta, Rapidash, etc.
Water: Ah, there are so many... Azumarill, Marill, Squirtle, Horsea, Lapras, Gyarados, Corsola, Mudkip, and all of the other cute ones.
Grass: Definitely Chikorita! It ranks up with Pikachu on the cute scale to me -- I adore it! <3 And also Belossom, Roselia, Oddish, Bulbasaur, etc.
Dark: Absol, I guess!
Psychic: Hmm... Espeon, Lugia, Mew, or Mewtwo.
Rock: Maybe Rhydon, or Kabuto?
Normal: Eevee, Togepi, Skitty, Clefairy, Ditto, and basically any of the other cute ones.
Electric: Pikachu -- Who else?! Okay, well... Raichu, Plusle, and Minun!
Ice: Articuno, because it's so pretty.
Fighting: Probably Hitmonchan, or Hitmonlee.
Poison: *scratches head* Vileplume, or Nidoran female.
Ground: Cubone's kind of cute, in an 'I-don't-know-why' sort of way, lol. I also like Phanpy.
Flying: Pidgeot, Pidgeotto, Pidgey, um... I can't seem to think of any others.
Bug: Beautifly and Butterfree
Ghost: Er, I have no idea! I guess I'll just go with Misdreavus.
Dragon: Latias, Rayquaza, Dratini, and Dragonite I suppose.
Steel: Um, Mawile?
Overall favorite pokemon: Ah, I have so many... I guess that I would have to say Pikachu.
Overall favorite type/s: Water, electric, normal, fire, and grass.
I couldn't find a list of the Johto Pokemon, so I probably left a lot of them out by accident, ehe.