My favorites are:
Tropical Malady
In the Mood for Love
Spirited Away
A Letter to Uncle Boonmee
Syndromes and a Century
City of God
Volver
Summer Hours
Crouching Tiger, Hidden Dragon
Cache'
Let the Right One In
Gomorrah
Pan's Labyrinth
Downfall
Spring, Summer, Fall, Winter... and Spring
Talk to Her
Worldly Desires
Mysterious Object at Noon
Amelie
Oldboy
Blissfully Yours