I suppose I'd say Ali because not only was he the man but he also had charisma.
I'm watching a Babe Ruth film at the moment and he seems like the man, when he was out but didn't agree with it he picked up some mud from the base and threw it in the umpires face. And when this bloke tried to wind him up he said "I'm gunna hit this one down your throat so you'll stop sucking on your mothers tit for a while"
I dunno if he really did those things or if it is just in the movie, but its funny as hell.