GFX Card support:
Voodoo3:
2d: Full Support
3d: Full Support
Voodoo4/5:
2d: Full Support
3d: V3 Mode - runs @ Voodoo3 speed but more GFX RAM
ATI Radeon (All)
2d: Full Support
3d: Full support upto 7500,.
The 8500 upwards will run, but only use features of the 7500 until W3D NG is released.
NVidia:
2d: None ATM, potential to exist however
3d: Aint a chance in hell - NVidia says kiss my arss
Matrox:
AGP Models only (and PCI equivalents)
2d: Full Support
3d: Upto the limitations of W3D (current version) until next generation W3D is released.
Personally I'm starting off with a Voodoo3 (With massive cooler and super overclocking) until W3D V2 is released then I'll buy the 9700 Pro card or maybe better.......
AGP is of course recommended because of the faster bandwidth (500mb/sec approx, compared to 128mb/sec approx PCI), and also texturing DMA operations capability.