Too tough a question. But nobody mentioned Ditka, nobody mentioned Charles Woodson, nobody mentioned Warren Sapp, nobody mentioned Bart Starr, nobody mentioned Thurman Thomas or Emmitt Smith, Charles Haley, Leon Lett, Dave Krieg, Steve Largent, Joe Namath, or even Deion Sanders or Jim Zorn--
Those guys are all at least worth mentioning, I think--but there are more, of course. Football's tough--I've been watching since the 70's--spanning 4 decades (God, I'm old)--and there are too many memorable games, too many great drives, too many great bowl games to say that there is one man out there (past or present) who stands head and shoulders above the rest.