Having read all the posts & taken some tidbits in along the way, I think it will be linked to the iTMS achieving 1bn songs. Sure there's gonna be ipod related announcements, nothing major tho, couple of upgrades possibly to shuffle, possible boom box etc...
I can see Steve announcing the major milestone in the company's history, how they started it all for the love of creating products and how the iTMS is all about the music etc, and then BOOM, a whole new product lineup allowing users to create music probably linked to Garageband, which includes the ill-fabled rumour of Asteroid - music started it all and where users can enjoy and have more fun in the creation.
I believe when Garageband was first announced in the keynote with John Mayer, Steve's words mentioned having fun in the creation of music.
All other incidentals, such as Logic express not going universal etc could be rolled in as Asteroid may not just be a music breakout box, but infact a whole production suite of gadgets linked exclusively with iLife (hence overblown MWSF'06 singing its praises!)
Either way not long to go, I'm probably way off, Asteroid or not, it's going to be an interesting few days!
Sorry, Final Cut Express not going universal.