This is not the future of the PC, but it probably is a new market sector: The Ultra Mobile PC (UMPC) is smaller than a sheet of paper, will weigh less than two pounds and integrate a full PC plus tablet PC features into a form factor that is between handhelds/PDAs and ultra portable notebooks. Since the notebook market grew by 40% last year, there obviously is a demand for more versatile, flexible or individual solutions.
The UMPC is likely to end up being the same thing that Microsoft targets with Origami, which is a stripped down version of Windows. Right now, the UMPCs we took a look at are based on a 915 chipset architecture and Celeron M or Pentium M processors, but it might not be long until we will see Core Duo based solutions.
This whole segment still is pretty new, and it is hard to gauge how the market will react. Personally, I would not want to have such an UMPC, as it is not going to replace my cell phone completely, and it is going to suffer from limitations such as device height and weight (yes, batteries are heavy) for quite some time. But we're eager to see first products and judge then.