I have been using the .3073 win2k drivers. In my setup, I have found these to be the most stable while offering the most features. I tried the latest DirectX 8 betas, but they were very unstable in my system.
However, I have heard from others that the latest betas are working great. I suggest then to check out Rage 3D, and give a few sets of drivers a spin. Make sure to properely uninstall and reinstall each time however.