I've taken a look at my favorite gangster/mafia/mob movies. I've decided to narrow it down to just 5 movies to make it a bit more difficult for myself. It seems that Al Pacino pretty much is essential for an excellent gangster movie. With a few exceptions. The list below is ordered chronologically. Here we go:
1. "The Godfather (1)" 
Actually I like Mario Puzo's novel better than the movie, but still it is a true classic in every way. Marlon Brando as Don Corleone with the timeless "I'm gonna make him an offer he can't refuse" and Al Pacino both guarantee outstanding quality. I've never been too happy with the sequels, but this first "Godfather" movie is excellent.
2. "Scarface" 
The ultimate gangster movie. As simple as that. Al Pacino is outstanding as Tony Montana, and the rest of the cast is top class as well. A fantastic soundtrack by Giorgio Moroder and endless one liners like "Say hello to my little friend!".
3. "Goodfellas" 
I couldn't really decide if I should pick this one or "Casino (1995)". Both are really cool movies and Joe Pesci is absolutely outstanding in both. Well, I didn't have enough room on my top 5 to pick both, so "Goodfellas" it is. Did I mention Joe Pesci as Tommy? Damn, he is one excellent sick psycho dude. Something I probably shouldn't say to his face...
4. "Carlito's Way (1)" 
Al Pacino does it again. Once again he is the main character in a world class gangster movie. Sean Penn's Kleinfeld is so fucked up, and so is John Leguizamo as Benny Blanco from the Bronx. I've never seen part 2 and I would imagine it to be total crap, so I never will.
5. "Donnie Brasco" 
Excellent movie with Al Pacino (yes, him again) as the old gangster Lefty and the police rat Donnie/Joe played by Johnny Depp. A true gangster classic with excellent acting and really cool scenes.