The dealbreaker for me is ability to use this to give a powerpoin presentation. If it can do that then it is a useful laptop replacement for road trips. Otherwise no deal.
Second priority is built in GPS support. With that the device is a slam dunk replacement for the proprietary systems that charge $125 a time for maps (4 required to cover just the US)
The other bizare choice here is to release this ahead of Vista without commiting to some sort of free upgrade scheme for the early adopters. I am not going to pay money for a machine running an O/S scheduled to become obsolete in 6 months.
That said, this really is going to be a game boy killer and a DVD player killer.