Just got my new rig today, posting here using it. [Vista Ultimate]
Had it all of about 4 hours at time of posting this
A bit early for me to say too much at this stage, as I never got to run the beta's to try it out ...although I did spend about half a day [using it] in my local comp store, causing plenty of glances my way from the staff there

When I went back a few days later to order the comp [along with Ultimate as the OS] they were more than glad that they'd let me use it for so long.
I'll post more in this thread as I get used to it more...
Spec's are:
Intel DG965WH mobo
Intel Core2 Duo 6600 @ 2.40GHz
2 Gigs DDR2 800 [mobo capable of 8Gigs with (maybe a) bios update][in future]
Nvidia 8800GTS w/640MB [current, available drivers]
LG Flatron L1919S Monitor
Vista Ultimate [OEM] 32 bit
320Gig SATA drive, partitioned.
Removable IDE rack
I still have to plug in my peripherals [HP Deskjet 5550 printer and HP Scanjet 4400C] to see whether they'll work...