For 2D graphics, pretty much any card should be easily good enough. The problem is with the NVidia drivers.
You can set render acceleration to on (it's off by default). Put
Option "RenderAccel" "True"
in the display device section of your xfree86config (next to the line saying driver "nvidia"). It's unstable on many systems, though, but it is faster. I found the 3123 drivers were faster than the 4xxx series, but they were unstable for me too.