How the conference is going to go:
Firstly, it is not going to be a press conference.
MS are going to structure this as an 'inside look' at the Xbox campus... there will be short segments with key team members who'll explain various aspects of the vision.
It will have a broad focus, just like the first MTV reveal of 360, they will not go into reams of detail on their strategy for the tech (primarily because they don't have the same system power)... this event will be all about celebrating the Xbox brand and its new found place as an entertainment (not just gaming) delivery device.
They will focus on the experiences the new system enables, why it changes the way you consume games and entertainment and demo integration with other devices.
Very few games will be revealed (why bother when the greatest games reveal event in the world will be a few days away?)
They will likely save launch date and price until E3.... save any thoughts of the bigger 'E3 event' type showman ship for E3. This isn't going to be like that.
It's going to be personal and candid - and about vision.
They will show the hardware and it is very unlikely they will mention used games or DRM.
Prepare yourselves... this event isn't aimed at Neogaf, so your console launch wet dreams should be put to one side... for now.