First you need to figure out what sort of games you want to play.. With Windows its essentially the hardware flexibility which makes the battle heavily in its favor.. You can basically choose what hardware you wish to purchase, even assemble them together yourself, install the OS, install some basic drivers and you are done.. Not so simple with the other OS's.. Also, you can basically keep upgrading your hardware or add new devices without any much hassle.. Again not so convenient with Mac or Linux.. Thus, Windows is the clear winner over here.. As for which version of windows, if you have a somewhat modern PC then Windows 7 64 Bit (anything except starter edition) is the one to get..