Is this a serious question? Rocky Marciano. He is the great white whale that many little Ahabs pursue obsesivley.
Marciano. His 49-0 record is like Babe Ruth's record of 714 career home runs. Its a magic number in boxing.
In order 1.Marciano 2.Lopez 3.Floyd(although will change) 4.Calzaghe The reason Lopez is two - strawweight will never be a category with big recognition, so for him to be undefeated for a very long time and have so many title defenses means something.