Hi, i am a windows fan and not so much os x. I don't know why i invested in a mac but i guess i was swayed by the unmatched pure beauty of the Macintosh computers, and perhaps on a lesser extent, the marketing and myths/facts about the system. Either way i've ended up with a macbook pro and despite being a windows user and fan, am not let down. I find that the only things i really dislike about os x is the dock and finder but anyways i'm not here to type a bloody blog. I use bootcamp and parallels desktop 6. I'd never used visualization before getting a mac but i'll admit, i love it, and parallels is my favorite program for os x by far. Anyways i run a windows 7 (32bit) bootcamp virtual machine. like the previous poster said, it has the capabilities of running 64 bit, but the programmers aren't utilizing the technology to it's fullest yet so it's not really a major benefit to go 64bit. This is actually a bit of a debatable subject but i'm pretty sure most people will agree with view. Anyways other than that, my windows 7 machine runs perfectly fine and the best part is, while i lack battery life in bootcamp; i run windows 7 in the virtual machine and get almost the same battery life as in os x. Windows 7 looks heaps better than xp in my opinion but to be honest windows 7 doesn't actually give me anything windows xp wouldn't. Just a tip though from something i heard, i'm pretty sure windows xp no longer supports updated for internet explorer so if that's the browser you use in xp (if you use xp to surf) you might want to stop and use an alternative free browser, they're better anyways.