Seb's right. Win2k is not "based around" Windows NT, it IS the new version of WinNT. NT5, to be exact.
But I have to disagree with you, Seb! Win9x and WinME are a bloated, buggy mess compared to Win2k. All the guys over at 3DFiles kept raving about how super stable Win2k was, and how it was even becoming great for games, so I had to try it!
So I installed Win2k and Service Pack 1, and ALL of my hardware was detected! As for games, I didn't believe it until I tried it, but Win2k runs 95% of my games as well or better than Win9x/ME. Games using the Q3 engine such as Alice and, well, Q3, actually run a few frames faster in Win2k!
Also Win2k is far more tweakable than 9x, and the networking aspect is much improved. I'm running a dual boot with 2k/ME right now and I barely use ME anymore. Dual-boot is the way to go though, just in case some of your games won't run (old DOS games) or you have some old hardware that doesn't have a Win2k driver yet.
All in all, I love it!