I'm am very happy with my Win 2000 Op Sys. It's the most stable MS system Iv'e ever used. Must be because it's based on NT. I have XP pro on several other systems and they are not nearly as stable.
So is XP. Win2K is NT 5 while XP is NT 5.1.
XP has many great features and I like it, but it is pretty unstable and can crash or have 'exceptions' for no particular reason.
Win2K is probably the most stable OS I've run yet (since DOS) and that includes Linux and OS/2.