Want of a 64bit OS is why I switched to Linux a few years ago. I picked up a Core2 laptop and was disappointed to see Windows Vista Home was a 32bit OS. I just did it because I figured I paid for a 64 bit microprocessor, so why not use "the whole thing."
Loaded up 64 bit Ubuntu and never looked back.
I should send Microsoft a note thanking them for being stingy with Windows. Up until that time I didn't have any beef against MS, and actually didn't think Vista was any better or worse than XP (although the actual delivered product was nothing at all like what was promised), but I couldn't figure out why they wanted to keep home users in the past. I guess it had more to do with maintaining compatibility with outdated hardware more than anything else.