I suspect that if Linux becomes a reasonable alternative to Windows, then it will affect new gamers more than it will affect current ones. Someone starting gaming on a PC will have the option between classic Windows, expensive flashy OS X or free but potentially missing features Linux. If Linux gets the support it deserves with drivers and games alike, then it could very well sway the decision. Of course, for this to work we need to start seeing Linux as an OS choice on pre-built machines. The Average Joe will just pick up a PC and use it, regardless of the OS on it. As a few have pointed out in this thread, some people don't even notice the difference - they just want the computer to do what they want it to.