There is a 64bit version of Windows XP, but you might run into some compatibility issues with programs like Norton Anti-Virus, who were made to reject 64bit, because they want you to buy the 64bit version of the program.
Windows Vista is also available in a 32bit and 64bit version, I have the 64bit version of Vista installed. I don't know if it was an update in the beta, or because it was the 64bit version, but I noticed an astonishing boost in performance on just about everything! Haven't tried Windows XP 64bit though, I'd be interested to see how it works. (My friend had done it, but he was very vague on everything he said, did more bragging then explaining.)
My dad built my cousins boyfriend a PC with Windows XP 64Bit and there were a LOT of runtime errors as well as compatibility issues. I would steer clear of 64Bit OS's til companies support the platform more. Just my opinion!!
anyways I'm glad to hear all this! I just had this little voice in my mind saying that 64bit XP turned into Vista or something. How is MMF2 in Vista 64bit? Sorry I've been away from Windows for too long to know about compatibility, is it like OSX and can run 32 and 64bit simultaneously?
How is Vista with dual monitors and bluetooth, drivers working for them?
Windows Vista 64bit runs Multimedia Fusion 2 beautifully, at least CR1 does. The same couldn't be said about the earlier beta, however I was using the 32bit version back then too. Not sure what was the cause, one way or another, but all I know is, the version of Vista I have installed, which is CR1, 64bit (the latest release), runs Multimedia Fusion 2 perfectly. The only extremely minor problem is the fact that Multimedia Fusion 2 matches Windows 98 and Windows XP better then it does Vista, so the Aero and 9x look sometimes tend to clash. Not physically, but visually, it's just not exactly appealing. Aside from that, it's perfect, the runtime and everything is very fast and pretty much flawless.
Multimedia Fusion 1.5 however, gave me problems when starting up.