Re: windows 64
Microsoft seems to be putting most of its 64 bit development into Windows Vista now instead of the the XP 64-bit version, so if you really want a 64 bit version of Windows, you may want to wait until Vista launches. Also, 64 bit applications aren't popular, so it's likely that you'll want to hold off on a 64-bit OS. There are known driver and compatiblity issues with 64-bit Windows, but if you know what you are doing, you can minimize that by researching for proper drivers.
Taken from Dell: "Peripherals you currently own or plan to purchase in the near future (cameras, printers, MP3 players, handheld devices) will most likely NOT work on a system purchased with Windows XP Professional x64, and some software applications may not work on the x64 operating system." Besides that, the gain is minimal or no gain at all in performance.
*Fact: Microsoft Window's Blue Screen of Death vs Computerforums.org's White Screen of Death. Which is worse?