Windows 2000 is the best WinOS out there.
Windows 2000 is the worst WinOS out there.
You'll hear both opinions from current, or sometimes even former, users of Microsoft's latest operating system.
Some things to remember. Windows 2000 itself is vastly more stable than the Win9x series. However, Win2000 has been out for a short time, so device drivers (such as the all important video card) haven't had much time to mature. Most complaints as to Win2000 can be traced back to the current state of available drivers, a situation that will improve after a little bit of time.
Windows 2000 is Windows NT 5.0, and therefore designed for use in non-home-use roles. What this means is that Win2000 has greater security measures, more control, extra features. If you are willing to put a small amount of time into learning the subtleties of the OS, you will find more flexibiliy and power than Win9x. However, all these included features come at a higher hardware resource cost (ie memory and cpu) as well as the extra time spent administrating your system.
Windows 2000 does included DirectX 7.0, plug and play, and most other Multimedia goodness that you can find in Windows98, Second Edition. I play Unreal Tournament under Windows 2000 with no problems (but then I also have set up UT for Linux, as well).
If you are interested in putting slightly more effort into your OS, Windows 2000 offers much more for you than the 9x series.
If, however, you just use your system to play games, surf the web and write emails to grandma, you might want to wait for Windows Millenium Edition. WinMe (yeah, I hate the name too) is the next in the 9x line, and should offer more stability than 9x. The operative word being should, in that this is still based on the same 9x kernel.
If you have any questions, though,
http://www.ntcompatible.com is a great place to get Win2000 tips and news.