Most Macs already come with a program called "Bootcamp," which enables you to dedicate a partition of your harddrive towards being another operating system. Simply put: It lets you install whatever OS you want and decide how much memory you want it to take up.
However, if you want Windows for it you will have to buy a legit CD copy.
Win7 might cost a bit, but you will be getting the full package; It'll run just like Windows, Bootcamp will help install any drivers you need, and you can even choose to have that as your main OS by having the computer start up with it automatically.
But you'll have to follow the instructions carefully and print out copies to make sure you install and partition it properly.
I have used Bootcamp with Win7 with great success. Although I prefer the Mac OS, I have had no problems using the Win7 side for things I couldn't get with OSX.
However, be aware that even if you install Windows, it will still use the hardware currently installed in your Mac. Meaning, if you have an old video card and a game requires a newer video card, the game will not run, even if you have Windows installed.
Otherwise you can try sticking to MMOs with Mac clients (there are a few out there), or play browser based MMOs like zOMG! or Runescape.
Topic: Are Mac's That Out of Base with MMOs (Read 1114 times)