Hard One but here it goes: 1. Harry Greb 2. Sugar Ray Robinson 3. Muhammad Ali 4. Henry Armstrong 5. Sugar Ray Leonard
Depends on how deep you want to go. Depends how you want to treat the p4p problem. If you go "all the way", it's Greb. If you allow, say, 10 wins, and allow for weight-jumping as impressive, Langford is #1. If you allow only for the best wins at a given weight, check out, for example, the lightweights of the 1940s. It's all very complicated and horrible. Awful.
It's across the weight spectrum ,but encompasses those such as Ali who only fought at heavy. Greb and Langford make the cut,imo.
