Can I use Windows 7 x64 on my iMac?

Hello MacRumors

I have a 27" iMac (specs in profile) and I have it bootcamped with windows XP right now to play windows only games on. I am going to upgrade to windows 7 and want to know if i should use x86 or x64. Also, can I upgrade my old windows version or go through the whole bootcamp process again and reformat? Thanks!

Cool, thanks. There is some contradiction info in that thread, if I just format the drive again and install 7 x64 I should be good to go right?

Thanks for the help I'm off to format!