Last night, I upgraded to XP service pack 2. It went very smoothly. The new wireless networking support is fantastic. I can finally unload the annoying software that came with the laptop to manage the networks.
I'm a little dissapointed with the firewall. It adds a few new features, but still doesn't seems as configurable as I'd like. We'll see...some more time with it may change my mind.
It was a very simple, smooth install. I would let any of my family or friends attempt it by themselves, and probably will.