Many can't diside witch 3Dcard they should buy, i would recormend a 3Dfx - (NOT Righteus 3D, because it sucks big time) or a PowerVR card:

The Diamond Monster 3D (3Dfx)  has fast 40ns EDO-RAM and the best quality 3Dfx voodoo chip around.
It can run op to 800*600 but officially only 640*480, but when running 800*600 it removes the Z-buffer so thats not a good idea. You may think it will be ugly in 640*480 but with the Bi-Linear Filtering and Tri-Linear Filtering (se Glossary) You won't notice, because no-matter how close you see the textures they wil smoothen out and still look very beautifull. Much more beautifull than 1600*1200 without Filtering. Example The 3Dfx can render 2.000.000 triangles pr. sec. compared too Playstations 200.000/sec. It is also a lot faster than N64 and Saturn. The 3Dfx is based on Triangles.
The 3Dfx can "only" run in 16bit (65.000) corlor because of the Z-buffer.

You may think that the PowerVR card sounds much better because it runs up to 1024*786 in 16bit/32bit. But it looks the same as the 3Dfx because the PowerVR card does'nt have Bi-Linear or Tri-Linear Filtering.
And because the 3Dfx is fastest I would buy it and not the PowerVR.
But when it comes down they are about the same, exept that the games boundled with the PowerVR are newer, better (but it also cost's about 70buck's more.

The PowerVR has fast SD-RAM, witch is faster than EDO, but the chipset is not as fast as the 3Dfx. But the PowerVR card can run resolutions up to 1024 with out removing the Z-buffer, because the card is based on planes and not Triangles. The PowerVR can run up to 32bit colors. But the PowerVR does not support Bi-Linear or Tri-Linear.

Glossary on the 3D - techwords can be found in my TechZone