Let's see if I can do a list of 20 (there are so many faves and loves and wows and ooh that made mes...)
In no particular order:
The Matrix (no, no forget the follow ups they suck big fat toe!)
Alien Quadrilogy
Pi
Paranoid Park
Last Tango in Paris
Spirited Away (just throw all the Miyazaki films in here)
Grave of the Fireflies
Feast
Crouching Tiger Hidden Dragon
The Bucket List
City of God
Ichi the Killer
The Revenge Triology (Mr. Vengeance, Old Boy and Lady Vengeance)
Fight Club
Juno
Equilibrium
Audition
Serenity
Das Experiment
Trainspotting
There are obviously many, many more like Some Like it Hot, Cowboy Bebop, Kill Bill vol I & II, Planet Terror and Death Proof, Balzac and the Little Chinese Seamstress, Three Seasons, Vertical Ray of the Sun, Delicatessen, Amelie, Metropolis, Wings of Desire, Blade Runner, Casshern, Azumi, House of Flying Daggers, Fargo, Memento, The Usual Suspects, anything by Guy Ritchie or M. Night Shayamalan, The Layer Cake, Benny & Joon, The Bridges of Madison County and Corpse Bride and my fave Xmas film ever The Nightmare Before Christmas...I could ramble on forever about films.