Pusher trilogy - Nicolas Winding Refn - All three in their own way essential Shitbag Noir.
Light Sleeper - Paul Schrader - Very underrated. Can you connect this movie to The Lost Boys in two moves?
Q&A - Sidney Lumet - Lost Lumet classic with Nick Nolte's best performance, plus Armand Assante with the most glorious long slickback in the history of crime cinema (and yes I'm including Jon Voight in Heat).
Short Eyes - Robert M. Young - Only recently discovered it myself, a great grimy prison story, (but not as good as Bad Boys the Sean Penn juvie tale) as dark and bloody as they come.
In the Cut - JaneCampion - Bless Pricilla Page for carrying the torch for this movie, unfairly maligned in its day by sexist creep critics. Deserves a total re-evaluation and a criterion re-release.