Microsoft's conference in a nutshell:
-CoD Modern Warfare 2: First to get DLC
-Epic: Exclusive XBLA game, Shadow Complex. Similar to the old Metroid and recent Castlevania games.
-Ubisoft showed Splinter Cell Conviction
-Crackdown 2
-Turn 10 announced Forza 3 with new render engine, in car views.
-Remedy: Showed Alan Wake. Gameplay shown, release for Spring 2010
-Square Enix showed FF13 running on the 360
-L4D 2 exclusive on PC/360
-Hideo Kojima appeared on stage to announce MGS Rising coming on 360
-Last.fm, Facebook and Twitter coming to Xbox
-New motion control like the Wii but without a controller. Kinda like the Eyetoy but better.
EDIT: Forgot to add that Bungie showed some Halo ODST gameplay, looks pretty good. And announced Halo Reach for 2010