I believe GF and II are the greatest movies ever made in America. But I don't count them as gangster or Mafia movies per se. I count them as a saga about a family with the Mafia as the defining milieu. Put another way: "Gone With the Wind" isn't a Civil War movie--it's about a family with the Civil War as the defining milieu.

IMO, the all-time greatest gangster movie was "White Heat," with "Goodfellas" and "Little Caesar" in the top three.