XP has some nice stuff for a home user. It's a great little OS that builds on the stability and performance of Win2k.
Skuzzy,
I agree, if you are running Win2k SP2, there is really no good reason to upgrade. Win2k is so good right now, I have no reason to mess with it.
Also, your Win98 machines are so stable because you very carefully and skillfully select the hardware that goes into them, and set them up properly. There is nothing wrong with 98 inherently, it just is not as robust as Win2k so it doesn't tolerate misconfiguration, flaky hardware, flaky drivers, and craploads of applications as well as Win2k does. My Win98 machine (I have one at home) runs perfectly fine as well... probably for the same reason yours does.
I bet Bloom25's would run pretty well too.
My recommendation: If you have Win9x... XP is a great upgrade in 6 months. Don't do it right now. If you are buying a new machine I'd go for it rather than upgrade later. If you have Win2k your likely good for at least a year. Heck, with the installed base and driver support, I'd even say that Win2k is a better gaming OS than XP right now. That will change in 6 months though.