Marco from Metal Slug. No bio-engineered super-body, no regenerating health, dies if shot with a single regular bullet, yet he defeats entire armies, blows up war machines the size of houses and fends off alien invasions, almost entirely without help.
Tank convoy? Give him a shotgun and he makes short work of it. Dozens of enemy submarines are attacking? He scuba dives and starts shooting them with his handgun. Zombies infect him? He keeps fighting, using his new zombie powers to puke lethal blood.
I think I've made my case.
Mufuggin' Ezio Auditore da Firenze. Dude's name alone is more awesome than half the guys on this list.
John Marston and my one-eyed bald lycanthrope Nord Dovahkiin tie for second place.
My Shepard would have been first if he hadn't decided to start having nightmares about dead little boys all of the sudden.