Linux is probably the best gaming system, but unfortunately all the games are made for windows so I guess you will have to go for that unless you want to mess around hacking linux to make it work
Hm, I suggest the Windows XP Gaming Edition.. It's a Gaming version of the XP os, mainly optimizing your gaming experience
I just suggested my opinion, but in legal matters XP is the only OS I know that is better for gaming.. Sorry
It's ok. That's what you know. When it comes to modern gaming however, 7 is the way to go becuase of DirectX11.