well i played a lot game using windows xp, and it's just working fine. don't know other OS for played game, basically there many game that require windows Xp.
dont think it really matters, probally want a new windows os like win 7, mac is good but not all game are made available for it and linux prob is not good for gaming due graphics and game are not made available for it
Windows 7 home premium, but if you don't mind a little more cost get Win 7 professional. And your processor will run 64bit version. With the 64bit Windows you get to use all of your 4gig's of RAM.
i cna say the best OS now is windows 7 Ultimate that is the best OS for playing latest game, but so far WIndows XP also can be used to playing latest game..
i only use XP to playing games but only PSX Games using emulator.
I think it has to be XP! I run Win 7 an would never go back to XP but its a great OS! Very economical! Uses little resources! But its low on features compared to 7 like Aero,Aero Snap and stuff like that. But Win 7 has the feature for installing drivers automatically instead of that annoying Windows Update window asking you what to do.
So:
7 for features.
XP for erm.. being sort of low resources.. it uses less of your computer and leaves more for your games.
win 7 x86 for non beast pc and win 7 x86 for beast pc. Ultimate is bst option. Install DirectX 11 FOr awesome game graphics and more realistics envirnment.