I love all those 30's gangster movies. I think Public Enemy is great too They were made before MPAA was formed and are a lot grittier than the crime\thrillers that followed. In fact the censors and the foundations of the ratings system were introduced as a result of these movies, which they thought glamorized organized crime and made children want to be gangsters.
You might remember Tony Soprano crying over the scene from this movie where his mother is making his bed.