Some trailers that show some interesting ideas coming to life:
Sanctum, looks like an interesting fusion of Tower Defence and FPS:
Elder Scrolls V Skyrim - the mighty franchise is ready to continue.
Battlefield 3 - how good does this animation and immersion look!
Cant go past another Portal 2 trailer (this is the Suction one):
The Duke Nukem Forever Trailer is a laugh and Dirt 3 looks great and the backing soundtrack works like a treat - many more of course - now back to Crysis2 actual gaming!