For me... my recommendations would have to be Fight Club, Donnie Darko and The 40 Year Old Virgin. Probably all mentioned already but all the more reason to see them

And for those who may like older black and white films I would suggest The Maltese Falcon. A classic 1941 (the remake) movie based on a novel (same name) starring Humphrey Bogart. I won't say more since it's pretty easy to figure things out with key things mentioned seeing as it's older, but still great.