Halo 4 looks to continue the fight in 2012. You'll apparently be back playing as the chief(somehow). I'm interested how well Microsoft and 343 studios will handle the franchise without Bungie for the first time.
Microsoft announced a ton of Kinect related titles including: Dance Central 2, a Disney themed adventure, as well as a kinect compatible version of Minecraft, and some others. The most important of these was Kinect Fun Labs, this is a trial of some of the major features Microsoft had promised us with the launch of the Kinect such as: Facial Recognition, Object scanning, and more.
Microsoft also announced that Youtube is coming to Xbox 360, which I think was a long time coming. UFC fights will also now be available via Xbox Live.
Keep checking back as I'll be updating regularly all week.