Well first of all I think apple are gonna say goodbye to the mac mini and say hello to the mac nano as a one more thing slot. Then they will announce iLife '07/08 with some really new innovative program(s) that no one has ever thought of before. About 35 new features in leopard that are going to be so amazing, you'll want to watch the keynote over and over again just to see them.
But I remain confident that a new iMac form factor will be introduced. I have two ideas of what it might be.
1. A really cool expandable imac where the computer is entirely on the back of the monitor (like the G5) Except, you can pull it off the back and expand it eaily. Also with this kind of form, you could change the screen size without having to buy a whole new imac
2. A really cool new imac where the entire computer is in a very flat base, and the monitor is projected in mid air so that you can put your hand through it. Ill make a simple diagram to show you what I mean:
_______________________
|____PROJECTER_________|
Screen that
you can put
your hand through
_______________________
|_______PROJECTOR______|
_________|-------|
_________/--------\
________/COMPUTER\
________|__________|
Both of these ideas would be really cool.
Lets see how accurate I am!
-Steven