Give the on board video chips some of there OWN RAM you can use a system like ati hypermemory and nvidia turbocache.
Open up the xeon cpu to chipset links so you have more choice in chipsets like AMD systems do.
Dump FB-DIMMS from xeon systems or make the same chipset with FB-DIMMS or DDR 2/3 ECC. The new xeno chipset with 2 pci-e 2.0 x16 slots should be FB-DIMM or DDR ECC.
Make the new chipsets with all pci-e 2.0 slots not some 2.0 and the rest 1.1 yes the new xeon chip with pci-e 2.0 will only have 2 slots with pci-e 2.0.
Go to true quad-core not 2 dual's linked by FSB.
Dump the FSB and go to the HT bus.
I agree with Joe Dragon, but add make exceptionally low power total system boards so battery times can be measured in days not hours. Make quad or oct core since when you use a device whether it be a computer or a handheld you want to be able to initiate as many simultaneous tasks as possible. Make multi-homing to a variety of wired and wireless access services a baseline function as well as some of the more interesting aspects of the internet. Remote ssh, ftp, pop, and tunneling to your designated servers. I want the whole world in my hand and I want to do nearly zero labor to access it once configured.