Chopper - An Australian "based-on-a-true-story" movie about the "career" of serial murderer, torturer and otherwise top bloke, Mark "Chopper" Read. Stars Eric Bana as Chopper in a performance that was praised by the real Mark Read, who assisted Bana in preparing for the role. Features a scene where Bana gets stabbed a dozen times and never once flinches because that's what happened to the real Mark Read. If you're at all familiar with the concept of "Insanity Wolf", Chopper is basically the human incarnation.
Kiss Kiss Bang Bang - Critically praised, but not promoted well. Stars Robert Downey Jr. as a former thief turned movie star and Val Kilmer as a gay private detective. Best on screen chemistry in a same sex couple until Simon Pegg and Nick Frost showed up. Part crime thriller, part noir mystery, part absurd action movie, all comedy. Really funny, really smart and extremely well made. I sing its praises so that somebody may finally see it for its glory.
In Bruges - Again, highly critically acclaimed, but a movie that so many people skipped over because it was marketed as a dumb action flick. It's actually a black comedy/drama that flickers between absurd humour and suicidal depression, sometimes in the exact same scene. It's a movie that is great at drawing you in to have the time of your life then kicks you in the balls to bring you back to Earth. Stars Colin Farrell as a one-time hitman (in his career best performance, in my opinion), Brendan Gleeson as a mentor type figure to Farrell and Ralph Fiennes as an underworld crime lord. It's well written, directed, acted and the scenery is fantastic. Comes with my extremely high recommendation.
The Usual Suspects - A movie I thought was quite popular until I got into a conversation with about a dozen people who were not even aware of its existence. An extremely good crime/mystery movie with solid performances from... Everyone who came into contact with the movie. Kevin Spacey is an absolute champion. As is Benicio Del Toro. And Stephen Baldwin. And Pete Postlethwaite... Everyone... I'm not sure if it really is underrated, but since there exists a breed of human being who are unfamiliar with the movie, I say I need to promote it as I can.