Superman vs. Muhammad Ali
Muhammad Ali may not be a superhero in the traditional sense, but to lots of fans, he was pretty frickin’ close. To have him face off against Superman in the comics just made sense, as two really important figures in completely kicking ass just have to fight against one another sooner or later. In this case, it came in comic book form way back in 1978, when comic book legends Denny O’Neill and Neal Adams teamed up to make this craziness a reality. It may not be exactly realistic, but it’s pretty awesome.