I have it running on my headless media server purely for the remote desktop - which is WAY better than VNC. Surfing the web and browsing content from a Pro Gear over a wireless Remote Desktop is actually faster than using the Pro Gear to do it natively
The other main bonus is boot speed - sooo much faster than 2000.
No reliability problems so far (except for a flakey graphics driver - replaced) although I've heard it is risky installing it as an upgrade - best to start over. My machine at work is an upgrade, though.
I think it's a little ill advised to run XP on the kind of machine that has an ISA NIC - or conversely to put an ISA NIC in a machine which is modern enough to run XP. You know PCI NIC's are like $15? Of course I'm biased because I work for a software company - I HATE users who don't upgrade to the latest stuff, and make our development/support requirements a total nightmare
Rob