I really want to add Donnie Darko to my list as well.
Mostly becayse I discovered on NS, in M&A where people were discussing the plot intricacies and ended downloading it.
One of the best movies of the last decade, and definitely one of the best debut movies of young directors ever... possibly even a Swan's Song, not at all ironic that one of the main songs in the movie is Love Will Tear Us Apart.
This movie kickstarted so many careers, and also gave way to so many dreams, wishes, hopes and theories on what really happened, I have to say this movie did really affect me in the terms of shots, editing, soundtrack and message.
I wish I was a teenager again...