I just picked up two 9600GTs for $75 USD, pretty good considering how well 9600GTs scale in SLI, also a 4870 512MB for $85 USD (FUGG YEAH), I'm probably gonna sell my 4850 once I get the 4870...
back to the original topic though, Windows 7 FTW, installed the $25 MSI motherboard into my system and didn't have to prep it or anything, Windows just booted right up, 975X chipset to P35, once it booted up I loaded all of the motherboard drivers and am on the MSI right now...