i have no idea why ppls think that Vista will slow your computer, it doesnt, i have played AH2 in Vista and i only lost 3FPS, and thats w/ 1.5GB of PC3200 and a 3GHz P4 (vista will rate the major parts of your computer, my CPU was the limiting factor, GPU was fastest factor.) but either way... i wonder you know all those DX7 and 8 cards that run DX9 wonder if DX10 could be the same way... running on DX9 cards. (P.S. FSX will have a patch to make it run under DX10 if wanted)
if you dont wanna wait you could always get an 8800GTX *sigh* or if you got the funds stick it w/ a Intel Core 2 eXtrem QX6700(its quad core) 4 GB of DDR2-800, a sound blaster X-Fi card, 3 WD Raptors (10,000 RPM) in RAID 5, and another 8800GTX, for SLI
*lol you dotn have to wait for 4 grand you can get one from some company, i dont remember its name though.*