Probably Houndoom.
Because I've never, never,
ever seen anyone do anything but compliment that critter. No complaints, no qualms with it's appearence, no nothing. It's pretty much always the pokémon that takes the crown in most dark/canine pokémon polls, and there are hundreds of people who seem to adore it. Hell, even
I kind of like it, and I'm hardly what one would call a fan of canines.
Grovyle, Breloom, Lucario, Magmar, Cacturne, Duskull, Typhlosion, Scizor, the Nidos, the Gardevoir family, Haunter, Jolteon, Aggron, Absol, Ludicolo, a couple of the clawed feline-ish critters, the legendary birds and couple of others I'm forgetting get honorable mention.
Combusken rules 'em all with an iron fist...uhh...clawed arm/wing, though. Why you ask? Quite simply, because personal bias is what makes a poll

That and the fact that
you don't get any cooler than a karate chicken, full stop, factual statement, word to yo momma, true as fudge cake.