First Appearance: Super Street Fighter II Turbo
The raging demon himself, Akuma would be higher on this list (And we know you WANT him to be higher on this list), but he's a character who must constantly be on the offense, because he takes a shit ton of damage when he's not.
Even so, Akuma is a monster. His air fireballs offset opponents, and his teleportation can throw off anybody in the right hands. Plus, his final attack (low punch, low punch, forward...) is probably the coolest in all of Street Fighter. He may have started as a joke in an EGM April Fools Day issue, but he's here to stay now. Hell yeah. Akuma rocks.