It is true that Windows is currently the best OS to play most games on, but that's only because the game developers are primarily programming for that platform. It wouldn't take too much to change to the point where Linux would be the best gaming OS, especially since it's a lot easier for people to get Linux as opposed to Windows. Linux isn't just your average freeware freeware app that you download from a site with 20 advertisements. It has been developed and imporved upon for many years by any skilled programmer who can possibly make it better. Since the whole thing is open source, it makes it a lot easier for just about any programmer to create applications to run in Linux, or even imporve upon Linux itself. And because Linux is mostly community based, everything gets tested much more than any commercial product. As for dumping Windows when you've already paid for it, you can keep it and still use Linux too. But keep in mind that when it comes time to upgrade, Windows still costs money where as most distros of Linux do not (especially to just upgrade).

Sorry for going on a little rant about that, but that's just some things I've thought about on the subject. I personally haven't switched to Linux yet, but only because I need another computer to do so. Half the programs I continuously run now were originally developed for Linux, so I already know there are several programs that I can rely on.