Bootcamp or VMware. my suggestion: don't buy mac if you're playing games not available on mac or stop playing those games.
i have win7 installed thru bootcamp, and each time I boot it up, I can't help but feel my blood boiling. why so? because it takes no more than 20s to boot up osx, but for win7 it takes more than a minute to reach the login screen, then another 15-20s for the start-up programs to load. and I swear besides SC2, the only other programs I have installed are anti-virus and google chrome.