The future spells DX10! That won't run on XP but Vista and the versions that come later like Vienna?! For newer hardwares that's always going to changing. With Vista the idea was geared around things like automatic repair tools as seen with the ability to fix startup problems by simply booting from the installation disk and selecting the options button at the bottom of the first screen instead of the "install now" seen there.
XP was geared more towards speed being the fastest to see the desktop after the ME flop several years ago and combined the NT core with the back compatibility with Fat. Having been out this long before Vista arrived it has seen more fixes and security updates while mainly geared for performance. The 8800s are to be followed by the 9800s apparently meaning everyone will be after those once the next line is out. The real problem is that the hardwares move faster then the OSs.