I'm bringing two random guys to the field, since all the good ones have been mentioned.
Obvious is Lionwhyte from Brutal Legend. He flies on his hair and screams his name in rage. He's a loser, but he's so much of a loser that it's great.
The second is that frog thingy from Devil May Cry 4. Not because of the fight, but because the prize for beating him is a briefcase of ULTIMATE DEATH.