Lots of good gameplay reveals from the MS conference so far. I had my doubts on Halo 4, but I'm excited about it again. Tomb Raider is looking great, and so is Splinter Cell. I think RE6 was the most mind blowing game of the MS conference, though.
South Park looks like an achievement for the sheer fact that the game appears indistinguishable from the actual TV show.
Halo 4:
Tomb Raider:
Resident Evil 6:
Forza Horizon:
COD:BLOPS2
South Park: The Stick of Truth