Steam actually was saying something about how their games run faster on Linux.
Valve* whose games run at 200 fps regardless of OS. They're just having a hissy fit because the Windows 8 model will potentially put a pinch on Steam software sales that they were trying to break into.
Most likely the game in question was using OpenGL, which is poorly supported by Windows drivers atm. If they recoded a DirectX game for Linux, the difference may be a lot smaller or favor Windows, but the reality is, it is not so easy to port a DirectX game to OpenGL, and most games are DirectX.
I agree with what most have said. In summary, you may get better performance out of Linux, but as the majority of games won't run on Linux, you most likely would rather trade quality for quantity and go with Win 7.
that was true 3 years ago but not now. windows 7 is the current best. 32bit or 64bit. with 64bit being the better again option for most people.
if your a retro gamer then 32bit may be the better choice as 32bit will install games that use a 16bit installer.
linux does use less resources as far as memory management goes but its emulating windows to play windows based games so its actually less efficient over all for performance. same with any emulating software.