Well, all Apple product lines are consistent and Apple only needs to upgrade Mac Mini. Mac Mini will receive Core 2 Duo and all the models with SuperDrive.
All Apple products will receive pre-N Wireless. MacBooks will get hard drives with flash.
Possibly it will be showed a MacBook Tablet, with a 12 inches screen, and a keyboard like the tablets of Windows world.
Everyone is starting with the points (like microsoft and nintendo) so i think that Apple will rename the gift cards of itunes to iPod Points or something like this.
And talking in iPod, probably we will see an iPod Video with 16 GB of NAND Flash. A new iPod Video will get out, and it will substitute the 80 GB iPod. The 30 GB will receive minor updates, but will not be replaced.
iTunes will be updated to work with the new iPod that will connect to iTunes via wireless, bluetooth or USB Cable. The updated iTunes will receive an iTV menu like the iPod menu in devices in iTunes 7. Movies and Music Videos will go to all European stores.
iTV will be introduced, with new features like iPod connection and PVR.
iPhone (if it exists) will be showed as iTV was in Showtime. They will call to the prototype "Apple Phone", but as a internal codename. Shipped in Q3 2007.
The Cinema Displays will be updated, with a new design, built-in iSights and another goodies. They will see a price reduction to be more competitive.
iLife will receive improvements like FTP upload in iWeb and upload to Google Video in iMovie.
iWork will receive a spreadsheet app called Lasso and Pages will be more word like.
Mac OS X Leopard will be introduced, and all features will be revealed. It will shipped in Late March.
And the one more thing will be an Home Server called xMac. It will be like a Mac Mini or the Cube, will be for the den, not for the living room, iTV will search for him in first place, it will be more powerfull that Mac Mini, but less that Mac Pro, with prices like the ones of iMac.
Steve jobs will bring to us a Even one more thing, where he will show that Apple is working in a new Game Console that will be based on Software for iTV and with wireless remotes.
This is my prediction to MacWorld.