The most powerful consumer (i.e gaming) card available at the moment is either the ATI Radeon 9800 or the nVidia GeForce FX 5900 (just released) - both are pretty level performance wise but the nVidia is marginally faster at higher resolutions. I'd go for the nVidia 'cause their driver support rocks.
My current "weapon of choice" is an Albatron GeForce 4 Ti4680 Turbo (actually an AGP x8 Ti4200) - It's overclocked to faster than Ti4600 specs and soft-modded into a Quadro4 980 XGL - works great with LightWave!
How to turn your GeForce 2,3 or 4 into a Quadro
