Ok so here is my Microsoft prediction list for what is going to go down at E3.
-Zune HD showed off new integration with Xbox and Xbox Live specifically in video
-Halo 3: ODST, Mass Effect 2, Alan Wake, Splinter Cell: Conviction, Forza Motorsport 3, All Points Bulletin, Lost Planet 2, new Lionhead game, new game(s) from Rare all shown off. All exclusive on the 360. LP2 may be timed exclusive
-Avatars heavily more implemented in Xbox Live and gaming
-Handful of Microsoft partnerships (Hulu perhaps)
-Full Motion Camera announced. Wont be tacky, actually quality.
-Crapload of new XBLA games
-Primetime channel release date announced
-New exclusives announced, a look into the future for what will be coming in future years
And that's about all I can predict right now with all the rumors I've gathered and sifted through to see what seems legit.