The GamerScoreBlog just posted this video, a little early it seems, going over the highlights of the Microsoft keynote. They spoke about:

Fable 2 - Press gets hands on, comes out in October, Xbox Live arcade brings gold into retail game. Peter Molyneux discusses co-op, and how you and a friend can play the online story mode.

Gears of War 2 - shows off new campaign level, discusses 5 player co-op multiplayer mode

Guitar Hero World Tour - 8 person multiplayer battle of the bands, and music studio

Rock Band 2 - Comes out in September, all DLC works on both games, new online and instrument options

Lips - exclusive to Xbox 360, motionless wireless microphones

Uno Rush - new XBLA title that uses the new avatar system

Galaga: Legions - same team that brought us Pac Man Championship Edition

Portal: Still Alive - coming to XBLA in 2008