Well, Windows Xp 64 has been out for quite a while now, I for one have already upgraded and there is a noticeable difference, better in some respects, while not better in other. The 'not better' part is driver support. 64Bit is the future, pretty soon all CPUs will be 64bit, so why would anyone want to run WinXp 32 with a 64bit CPU, isn't that like putting Ultra High Test Premium gas in a Yugo?
There are no drivers for most of the hardware I own, sure there are workarounds I can do to get my hardware to work, but it is a workaround.. Check out the full article over here.