Vista on the desktop I just built. It was meant for gaming so gotta have Windows on it otherwise I'd be running ubuntu or xp. On my laptop, I run ubuntu. Gotta say the linux OS's are pretty good for your average PC user and I guess I'm a fan of the open source world.

my only grudge is how you have to pay 130 dollars for an os upgrade which I believe to be bullshit.
I also find that to be utter bullshit.