This thread is inspired by the worst boxers thread, as that one has shown that there are more than a few Mudcat boxing fans.
Speculating on who would have beaten who is the stuff of boxing fans, and, though we'll never really know for sure, it still makes for interesting discussion. So, what's your heavyweight ranking? Here's mine, for whatever it's worth.

1. Muhammad Ali
2. Joe Louis
3. Jack Johnson
4. Jack Dempsey
5. Rocky Marciano
6. Sonny Liston
7. Sam Langford
8. Jim Jeffries
9. George Foreman
10. Mike Tyson
11. Larry Holmes
12. Joe Frazier