The big question with Xbox, I think, is regards to how long out they're going to announce games and projects.
They probably have a fair amount cooking that could lead to some big pops and crowd reactions at a conference. However, that short term buzz can lead to long term backlash, as we've already seen with games like Crackdown and Scalebound. With less games than the others, though, I can understand why they'd give in to the pressure.
That's one of the reasons I think the "it's not a good conference without big surprise announcements" crowd is poison.