Thinking about it, Microsoft could actually have quite a well rounded conference for the first time since 2009. Halo 4 and Forza: Horizon both look like really fresh takes on their respective series, whereas Microsoft's Vancouver's project could add some real depth to their first party lineup. I imagine that they'll also showcase Class3. The game's way too ambitious and unique to miss out on the E3 conference.
In terms of Kinect, well what trend have we been seeing since the start? Microsoft are following the Kinect + Big Name IP tactic. We've seen Kinect Star Wars, Kinect Sesame Street, come this year I imagine we'll see some kind of Kinect Marvel/Disney/Lord of the Rings or Pixar focused title to be the next big thing following Kinect Star Wars.
Third Party? I fully expect to see Versus XIII, there's literally no reason for it to not be on the Xbox 360. I don't expect to see Respawn's project, that's more likely for the Sony stage. HOWEVER, if Bungie are ready to show off their new title. I fully expect to see it on the Microsoft stage.
Finally, the media partnerships. I imagine they'll do something to switchup the XBL Gold/Silver membership passage, there are tonnes of silver members they know they could probably instantly get back if they allowed them to play online games over xbl for free. We'll probably see the debute of Xbox music, elaboration on Xbox TV and finally some kinda of partnership between Microsoft and say...Spotify.