My definite bet would be VOODOO 3 3000 !!! Its a GREAT card, it made MIRACLES for my "old" computer:AMD k6 200 mhz and 64 mb ram. I had like 9 fps in Quake 2 at 800x600 without the V3 3k, after installing it I get 140 fps!! Good rates in Q3 too: 35 fps, 640x480, medium detail graphics.
For your system,
I would recommend the Voodoo 3 3000 - it should outperform the TNT2 M64 by a reasonable margin in most games. The Diamond Stealth III is an interesting choice, if you like messing about with drivers alot, then it might be the way to go, it's performance in OpenGL and using S3's MeTaL driver is pretty good, but it sucks in DirectX, and has terrible driver support. Using MeTaL the Stealth should beat the Voodoo 3, but not very many games support MeTaL (i.e. Unreal Tournament, and a few other minor games I can't even remember).
Just my thoughts.
P.S. If you are getting a V3 or a Stealth III, look towards getting a graphics fan for them - they really do need them.
FORGET THE m64 !!!! The v3 3000 is ALOT faster than that ****-card in all the benchmarks!! M64 has only 64 bit graphics, while V3 has 128. The V3 also has much more pixe-per-second etc values. www.3dfx.comwww.nvidia.com
check out their data's and you'll see what I mean.