People are gonna' disagree, but based on this criterion:
I'd pick Tank Abbot. I'm thinking bar scene type fight, not squaring off, touching gloves, w/ some room to maneuver. I'm thinking out of the blue, you bump shoulders w/ someone in a crowded bar, and it turns out to be Tank . . . his size, power, and rhino-style punching would pretty much murder anyone, given those circumstances.