I'm currently putting Ian through a masterclass in gangster/mobster films - I'm educating myself more than anything, and have come to realise there's a lot to love about these kinds of films!
Below is a list of what we've seen, and another list of what we're planning to see:
SEEN
The Godfather
The Godfather II
Goodfellas
Mean Streets
The Departed
Scarface
TO SEE
Carlito's Way
Casino
Infernal Affairs
Eastern Promises
A History of Violence
Ransom (tenuous, I know!)
So, come on, what have I missed out off the list? Is Heat a gangster flick? Does just about anything with de Niro or Pacino qualify? And since when was Joe Pesci so freaking messed up?
This is a 
Heat is just damn good and you need to watch it!
OH you are watching such a great genre! I LOVE mobster movies. Good Fellas (as violent as it is) is brilliant.
Heat is brilliant! The Departed is INCREDIBLE!
you gotta see "Blow" with johnny depp. kinda gangster/drug lord type of stuff. and you can't go wrong with johnny depp...yum yum!