For me its gotta be the undefeated Marciano, but if I had an argument with myself, it would be to say, ey up lad Chavez what about him lol,

Then I would reply yeah but he got beat Rocky didn't, then Id reply yeah thats because he only had half as many fights or so....

Aaaaah then id get confused when a third me says ...scuse me what about Mr Pep.....then id go back to sleep after telling myself....oh shurrup just pick all listed lol,

But seriously tho, Rocky for me.......
And I dint mean Balboa lol..he is real ain't he...