I recently had a quick look at Win7 Pro but at the moment can’t see any reason to switch from XP Pro and have to reinstall all my programs again. My XP is rock stable and does everything I need, faultlessly. It hibernates at the touch of a key and takes only 20 secs to wake up again. Occasionally I reboot it, but most of the time I just use hibernation and it never misses a beat.
I got a bit tired of the standard XP theme with its bright colours so I recently installed the WinXP “Royale Theme” from:
http://www.softpedia.com/get/Desktop-Enhancements/Themes/Royale-Theme-for-WinXP.shtml
Check out the screenshots. The smart soft blue curvy task bar and title bars makes it look like a new machine so if you’re happy with your XP but would just like to smarten it up a bit, it's well worth a try.