For the people saying Tyson for boxing, as far as power goes, I don't totally disagree, but you should also check out Ernie "The Acorn" Shavers. That man had a right rand that would make even Tyson's pale in comparison. Most of the all-time greats ducked him because of his vicious punching power. Muhammad Ali said himself that he had the hardest punch. Even Tyson refused to fight him when Shavers was over 40 years old because he feared Ernie's power. He had a suspect chin and sometimes poor cardio, but his punching power was scary. One of my favorite Ali quotes ever was about Shavers. "He hit me so hard, he shook my kinsmen back in Africa"
Edit: Here is a video of Lyle vs. Shaverspart 1
Shavers is in the blue. Lyle was such a freakin warrior too.