nVidia uses a single driver for almost all of their cards, so just choose one that is within your budget and will work in your computer. By that I mean find out if you need PCI-E, AGP, or even plain old PCI. PCI-E is what is used in modern computers.
See here for more information about PCI-E: [url]http://en.wikipedia.org/wiki/Pci-e[\url]