RE: I Still Don't Get It
Whichever one does what you need it to. There is no "best" here. Windows excel at playing games (I'll throw in a caveat - XP excels; Vista's a piece of ----); Linux can save your butt and your data if your Windows hard drive crashes and you've been stupid and haven't backed it up lately; and Macs will run all three OSs, some better than others, if you are looking for an all-arounder and your games don't require the blazing speed of an XP based gaming PC and you don't feel like going the boot camp route.
It all comes down to the right tool for the right job. That's all the computer and its OS is - a tool. This isn't Sunday school and we aren't learning the Ten Commandments here (but all the fanbois would have you think otherwise): "Thou shalt have no other OS but Me!" sort of thing. In short, the best OS, and the best computer, is the one that works best for YOU, whether it is Mac Tiger/Leopard, Windows XP/Vista, or any of the many flavors of Linux/Unix.