Capone and Gotti are the most popular. One wasn't even Mafia, he contracted syphilis and died before he was 50. The other one was boastful and too flashy, making his son, only half italian a boss.
I chose Bruno, even though he was quieter, he ended up with his head blown through. Out of all of these, the closest to perfection is Costello and yet he is at 0!