I'm always interested in seeing movies that others find great.
A few of my recommendations: Adaptation, Before Sunrise, Before Sunset, A Moment to Remember (Korean movie; saddest movie I've ever seen), A Bronx Tale (I'm sure most have seen this one, but if not....)
Currently on my Must See list: Synecdoche, New York (I can't wait for this one!! Charlie Kaufman is by far my favorite screenwriter and he's actually directing this one. I'm really interested to see what a film that he wrote looks like when he's the one behind the camera.)