Bo Jackson ... I'd say the best NFL running back of all time. Had he not been injured, he would have put up some prolific numbers. Only RB in history to have two TD runs of 90 or more yards. Mixture of speed and strength. Add to that his baseball career ... man, what an athlete. Also, was the best video game running back of all time ... in the Techmo Bowl game on the first Playstation.
Bo Jackson. The greatest athlete you will ever see. He has no significant record in his unfortunately short-lived baseball and football careers that should qualify him, but his unmatched athletic prowess and two-sport excellent play should garner his election to both the baseball and football Hall Of Fame.