I'm not expecting much. They could announce Alan Wake 2 (or something Alan Wake related) or the very unlikely Lost Odyssey 2 and that would make me happy, but I really, really doubt it. Their press conference will probably be filled with 3rd party demoes of games we know about, a Halo 4 demo, then a bunch of Kinect. If any new games are announced, they are likely insignificant titles. Honestly, my expectations are incredibly low for Microsoft.
Food for thought: Shove an apple in your brain