I had Vista 64bit on my first build with BF3 Demo and everything worked fine. The only problem I noticed was that you can't have two things installing at once, it would pause one install until the other one was finished. I upgraded to 7 now.
I've heard Windows 8 will be annoying for PC gamers because it's going to copy the game shortcuts in several different locations, little things like that.
Also, let's get back on topic
You can get XP to run games like BF3 with an unofficial Direct X10 port.
Windows XP only went up to Direct X9, but many have ported Direct X10 back to XP.
Microsoft needs to re-make XP or Start Working on Project Longhorn again.
I'm already Re-Making XP using unofficial ports of things made for Windows Vista and 7.
Sucks that Microsoft dropped the deadline of XP Support from 2024 to 2014.
Seriously WTF Microsoft I know you guys want people to move on but XP is used by a variety of companies, if you don't believe me go check the site, they want people to upgrade to 7.