Just curious how many of you have a 64-bit OS. To check for Vista or Windows 7, go Start, right-click Computer, select Properties, and it's listed under 'System type' (eg. "64-bit operating system"). I've forgotten how to check on XP
Note this is different to having a 64-bit CPU. You can still install a 32-bit OS on a 64-bit CPU, and most CPUs these days support 64-bit, but I'm sure there are still a lot of 32-bit OSs around (mainly due to XP).
I'm not going to be coding anything 64-bit any time soon (the only benefit is possibly a small performance gain on 64-bit systems, and involves substantial code maintenance), but it'd be interesting to know how far 64 bit has gotten these days.