Hmm. Y’know, I’ve never actually gone through them all and thought about it. Let’s see…
(For convenience’s sake, I’ll assume that one element is ‘dominant’ for any Pokémon that have two – otherwise, a lot of these will appear twice. Also, de gustibus non disputandum – these are my personal favourites, and not the ones I necessarily think have the best or most interesting designs and concepts, though there is naturally some overlap.)
Grass – my favourite Pokémon of all is, and has always been, Vileplume, whom I consider to be in many ways the archetypal Grass Pokémon: peaceful, tranquil, but able to hit back with downright sadistic disabling attacks when provoked.
Fire – Ninetales, elegant, clever, enigmatic, and terrifyingly vengeful – reminds me of a Greek goddess. I’ve always had a soft spot for Camerupt too.
Ground – Marowak. What can I say? I like darker takes on Pokémon, and Marowak is one of the cooler ones.
Poison – Mmm… probably Nidoqueen; a mother’s love, wrapped up in a battle-tank body.
Electric – Ampharos. This is the GSC nostalgia talking; I’m not even going to try to deny it.
Water – My favourite is Milotic, but there are a lot of other Water-types I love as well; Starmie, Carracosta, Kingdra, Relicanth, Octillery, Gastrodon… I could go on.
Rock – Hmm. This one’s tough, but I’m probably going to go with Rampardos, partly because dinosaurs are awesome and partly because, like I always say, there’s no ‘kill’ like overkill.
Flying – I’ve never been much of a Flying-type kind of dude… probably Archeops, with an honourable mention to Tropius for having such a crazy awesome design.
Ice – Froslass, who does the whole ‘mysterious wandering spirit’ thing so very, very well.
Normal – There are so many it’s hard to choose, but I’m going to go with Dunsparce, because Dunsparce needs more love.
Bug – mmm… tricky… I want to say Venomoth, but I’m also very tempted by Masquerain and Galvantula, both of whom I think have really interesting designs… call this one a three-way tie.
Ghost – Spiritomb, who is literally made of the imprisoned souls of 108 unrepentant murderers, has always been the one for me.
Fighting – Mienshao, hands down, for totally redefining how Game Freak design Fighting-types.
Dragon – Am I allowed to say Kingdra? Eh, she already got a mention… let’s go with Flygon, because Flygon is awesome.
Psychic – Sigilyph. The archaeology fanboy in me just can’t go past this one.
Dark – Houndoom, probably, with Umbreon and Absol a close second and third.
Steel – Bronzong, just for being friggin’ indestructible.
Pokémaniacal 