Vito Corleaone -> Frank Costello, Joe Profaci and Carlo Gambino
Luca Brasi -> is for me a little bit like Frank Sheeran for Russel Buffalino or Richi Kuklinski for Roy DeMeo,if the Carlo-Story is true

Hyman Roth -> of course Meyer Lansky
Michael Corleone reminds me a little bit on Bill Bonanno (I am reading "Honor Thy Father", at the moment)
personally, I wish they would have done rather movies about the real charakters, not fictional versions of them...