Wow, that's tough to narrow down!
I really love:
Seven Samurai (of course!)
The Bicycle Thief
Tampopo
Spirit of the Beehive
Women on the Verge of a Nervous Breakdown
The Devil's Backbone (disturbing subject matter alert)
Sholay (Hindi version of a Spaghetti Western -- if you're intersted in Indian movies at all I can recommend a ton more)
The Good, the Bad, and the Ugly or Once Upon a Time in the West or For a Fistful of Dollars
The Conformist
Kung Fu Hustle
A Chinese Ghost Story (utterly wacky and tons of fun)
The Garden of the Finzi Continis (it's slow, though -- be prepared going in)
The Gerard Depardieu version of Cyrano de Bergerac
La Dolce Vita
The Cocteau version of Beauty and the Beast
The Fourth Man (utterly bizarre)
Delicatessen (also utterly bizarre, but oddly sweet for a movie with so much cannibalism)
Diva
Full Moon in Paris
Shall We Dance (the Japanese original, not the American remake)
OK, that's way more than three, and I could keep going but I'll try to restrain myself. My list is a little heavier on weird movies than others because I like that sort of thing, but there are also some comedies and romances on there.