Since I've fixed my old Dell Dimension with Windows 7 Ultimate installed fresh, I've had problems and learned that there are no drivers for the nVidia mx420 on Windows 7. The 420 isn't great, but combined with my RAM and System Speed it was pretty good. The onboard video is very crappy, cannot even play Half-Life 1 at 680x480 on Software, I get like 8-10 fps average.
So, if you're still reading (thanks) - I'm looking for a video card that's "average" or "good" that is PCI 1.0, which is what my motherboard supports. It needs to be able to run on Windows 7, ie: Have drivers compatible with it so I can use it and game a little bit.