My favorite gangster movie is The Godfather Part 2. I like the way it goes back and forth between the two different stories. It's interesting how Vito Corleone and Don Michael Corleone personalities change as they become more involved with the inner workings of the mafia.
I also like that it goes to black and white when it cuts back to Vitos early years. It's a good way of letting us know, this happened long ago.
It's also interesting to watch Michael Corleone juggle raising his family, and his Mob life.
It has been a while since I have watched this movie. I think I am going to watch it again.
I guess Goodfellas is probably the best gangster movie ever made, but I also like Scarface (1983) alot. The old Cagney, Bogart, Edward G. Robinson, et al, ganster movies were great also. The Godfather and The Godfather Part II, of course.
I'm not going to say this is my favorite gangster movie, but I recently watched "The Ice Harvest" and it is worth checking out. It has a dramatic story line with lots of twists and subtle hints which I love. Now I am not really a fan of John Cusack or Billy Bob Thorton for that fact, but they actually do a good job of portraying the "none-gangster" gangster (if that makes sense) Like I said it's worth checking out, at the very least you shouldn't feel like you wasted 2 hours of your life when you are done watching it.
I really like the Godfather movies also, but I think that I liked the 3rd one better. I am not sure though it has been a long time since I've watched them. I am glad that you brought this up because I want to watch them again too.
I forgot one that I would like to recommend. I really liked Once Upon A Time in America. This was made by the same guy who made The Good, The Bad, and The Ugly. This movie is great if you like him. There is not a lot of dialog. He likes to tell his movies through the cinema and not so much with the characters talking. I really liked this movie because it really shows how people had to live in the early 1900's just to survive, and how kids that are left to fend for themselves make do with what they have. It really shows how the streets turn kids into criminals so they can have something in their lives. I would have done a review for you guys, but it is a long movie, and I didn't have enough time.