Vista 64 bit
Im using it at the moment on a new box.
UAC can be turned off
File copying is slow
Problem with running my monitor with a combined DVI VGA connector, BSOD every time it started, got round that but getting a DVI to VGA adapter, then sticking a VGA to DVI adaptor on the end, then plugging it in. Works ok.
If the PC goes into sleep then it cant bring the monitor or mouse back out of sleep.
Cant seem to copy files to another vista computer across the network (no matter how I fiddle with the perms), but its fine copying files to an XP box
Loads of services keep stopping, but Im not sure why, or sometimes even what the service is for that has stopped, doesnt seem to effect anything.
Something wrong with font scaling, or something, it looks fine after you restart the app, but after a resolution change everything looks a bit dodge.
Overall though I have to say I had worse with 98 1st edition and ME.
It depends what you want from your computer experience I think. If you want to hack, then you know this is not for you. If you want to play DX10 games, then you really don't get much choice, do you ?