First and foremost WM needs an UI overhaul, use the lessons learned from Windows Media Center, the interface designed to be usable at 10 feet, I think would also work incredibly well at 10 inches, Sony has one that works on the PSP, Apple has one for the IPhone, Microsoft needs one as well.
AV out ala Zune, should be standard (nice accessory sale on cables)
Support for audio BT headset, music on a wireless headset, what a concept...
Stronger, simpler, easier sync, needs to just work, bottom line, heck worse case scenario treat device like thumb drive and folder sync.
Mini-usb ports for easy use of peripherials like thumb drives and keyboards
The best and most powerful websurfing experience possible...nuff said
Side show support
Mini-explorer that that has freakin scroll bars, hate that I have to use the rename feature to look at a long file name....hate kludges
