In a year from now (when extended phase support dies out for my Windows XP x64 Edition), I plan to install Windows Vista x64 Utimate Edition. I have ran a test install for a couple of weeks. I find that, except for the boot logo and Weclome Screen taking twice a long to load, I have managed to tweak Vista x64 to the point that it's besically as fast as XP in Basic Mode, once the desktop appears. In fact it runs REALLY well! I am using an HP xw8200 Workstation with 7 GB of RAM, and two Xeon CPUs at 3.66 GHz.