Top Secret and Airplane are the best comedies ever. It took way too long for The Shawshank Redemption to get mentioned. But for me anything by Darren Aronofsky, Snately Kubrick, or Sam Mendes is a guarenteed winner.
Pi bugged me because there are a lot of little details that were somewhat borked - opening sequence of pi is wrong at the eighth or ninth place, the wrong letter is used to refer to the golden ratio, a relatively easy problem was used to show off the main character's mad division skills... interesting film all the same, but about fifteen with a mathematician right before release would have cleared all of that up.
I'm just gonna say Pulp Fiction or fight club 'cause there's tons of gay shit I don't dare to confess, such as feeling badly depressed for several weeks after watching Bridge to Terabithia and enjoying all of the Pirates of the Caribbean movies a lot.
By the way, has anyone here seen Equilibrium/Cubic? Even considering the low budget, that one kicked Matrix's arse with a five-foot plank.