The Departed, hands down.
As for a list:
1. The Departed
2. Lord of the Rings: Return of the King
3. Gladiator
4. Chicago
5. A Beautiful Mind
6. Slumdog Millionaire
7. No Country For Old Men
8. Crash
9. The Hurt Locker
10. Million Dollar Baby
(I actually hate this movie, even though I loved Mystic River and Letters from Iwo Jima)
The irony is only The Departed and Gladiator--maybe ROTK, as well--were the actual best films of their years. All the others I can think of anywhere between 2-15 that I thought were better. But that's just the Academy, eh?