TBH, if you are a gamer and can't part with your PC games, then I wouldn't suggest switching and banking on "Virtualization". Rather, I would suggest that you keep your gaming rig solely for games and all the other stuff Linux....
As for virtualization, what Jack said. Where you have a program that sits as a translation layer between the software you want to run and the "foreign" operating system that wouldn't "understand" the software without the "translator"....I don't know if this is right technically but this is how I understand it....