I know of tons of organizations that are still running XP Professional on their networks trouble free, which was my experience as well. I've moved on to Windows 7 but my experience with a PC running XP was a huge upgrade from a G3 running OSX. It wouldn't work with any peripherals without an Apple logo, it was murder to connect to a non-Apple server, and it locked up if I opened more than 2 programs simultaneously.
It made for a nice little music player, the screen was very nice, and I went through 3 chargers in a year. When, a year in, I had to wiggle the hinge on the back to get the screen to come on, I had enough of the hardware and operating system.
I'd use one again to display photos or arrange music but I'd never trust important work to the fruit again.
