I think Louis or Ai have got to be the favorites. The thing about those two is I'm not really sure we saw either's absolute best. Ali didn't fight from age what? 24-27? And Joe Louis at what 27 just about stopped fighting for 2-3 years due to WWII. A scary thought.

The other guy who leaps to mind who would have been a monstrously tough out on his best night? Sonny Liston.