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!