Nice mid-range card that will let you play with Shaders...

The 9600 and 9800 series are both pretty cheap in the States now.

As far as cards in general:
http://www.techlogic.ca/directx/caps/query.mv
Select Shader information and it gives a listing based off from the DirectX Dialogue of various video cards and the shader version supported by them. Unfortunately since it is based off from DirectX 8 - it only lists vertex shader 1.1 and pixel shader 1.4 or below.