Hey Guys,
I should give you guys an update!
I settled on XP Pro, as a friend of mine basically gave me his license since he's not using it.
I was stunned by how smoothly the changeover went. Installing XP was a breeze. Running thru the basic tweaks to turn off all the graphic whizbangs, etc, didn't take long, and to my amazement- everything is just as snappy as Win98SE.
Coming from Win98SE, I fully expected my machine to get bogged down by XP. But, it looks like I can wait a little longer to update hardware-- my trusty P3 1ghz, Intel D815eea, 512mb ram, separate hard disks for apps and audio. It's doing just fine.
Cubase SX 2.01, MIDEX 8, Wavelab and Halion, then SFP 3.1c, all installed and worked first time. Reinstalling Emagic LAP 4.8.1 on the other hand did not work at all, until I called Emagic (now Apple!), and they sent me a CD installer "Volume 13 CD" which allowed me to install 4.8.1 on XP and get back to some of my old data.
Overall, I'm *extremely* happy, and wish I'd done this sooner. I'm really liking SX, and all my tools seem to be working happily together.
One more detail: my impression is that XP starts up way faster than Win2k. (My development machine is Win2k on a P4 1.7ghz, and takes muuuch longer to start up!)
Thanks again to all those who gave me advice here!
-John