If you are after
stability for your home computer used to surf the internet, Windows
2000 is a great operating system.  But, if you’re an avid gamer,
your best bet would be to stick with Windows 9x.  There are two
main problems with Windows 2000 and games.

First of all, being

Windows 2000 doesn’t have the exact same subsystem as Windows 9x, it
won’t interact with your hardware like Windows 9x.  Therefore,
games written to make your sound or 3D card do one thing under
Windows 9x might not be able to do the same thing under Windows
2000.  This is due to a lot of things, including the fact that
Windows 2000 is a purely 32bit operating system and some games
still use 16-bit access to some things.  Sometimes it’s due to
the inability to produce a driver for the hardware in the Windows NT
subsystem. It should be noted, though, that Win2000 does come
packaged with DirectX 7.0, so 32-bit games designed for this API
will probably work fine under Win2000. I have tested some of the
popular modern gaming titles and most seem to work fine under
Win2000.

As of now, a major
problem with Windows 2000 is the lack of third party driver support,
just as with any newly released operating system.  Chances are that
if your hardware isn’t natively supported by Windows 2000 (i.e. the
driver is built in), and your hardware isn’t made by a major
competing company, like 3Dfx or nVIDIA, you probably won’t be able to
use that hardware for a while.  PC Mechanic experienced
problems with a 3Dfx based card.  One of the test systems had a
Canopus Pure 3D I card installed.  The Pure3D is a pass though
card, using the VoodooI chipset, so we still had
support for SVGA resolutions.  Windows 2000 only identified the
hardware as a "Multimedia Video Device." 3D performance
then dropped noticeably
because of the lack of support for the 3D card. 
Canopus does provide NT 4.0 drivers for the Pure 3D, but they didn’t
seem to work under Windows 2000.  That, and the drivers only
provided OpenGL support, which causes poor gaming support for the
average user.  OpenGL is only one of many APIs in the world,
and supporting only OpenGL leaves out support for Direct3D, which is
a major API in the 3D world.

Windows 2000 also lacks
native DOS support.  That is because it’s a pure 32Bit GUI

Operating system.  It does have the ability to emulate DOS, but
it will not be a "true" DOS operating system.  This can lead to some compatibility problems with DOS
games and programs.  Check with your software creator
before you use DOS programs on a Windows 2000 Machine.