I haven't even looked at my processes until now... since you mentioned it. I have the following running ALL THE TIME while flying...
1) Seti at Home screen saver
2) Black Ice (firewall software)
3) ICQ
Since you asked, my system is running 2% busy right now while I type this, and my memory usage is 16k available (Netscape active). I don't know what it is when flying, but may check it later.
I don't think Win2k is bad at all and compares favorably with Win98 performance wise.
Remember, this is with a PentiumPro 200 MHZ running Win2k Server. Yes the Nvidia TNT chip does a lot, but not nearly as much as some of the newer chips.
If you have slow performance, I'd look elsewhere, Win2k is pretty solid.
Dhog out.