The definitive answer was/is the PCI 6200. This might be a contender, but there are some worrisome issues.
A: the card design reflects that of a 64bit memory architecture which would cripple memory bandwidth (can't find specs to confirm or deny this speculation)
B: price; obviously if you can somehow get the performance out of the PCI bus, you should be willing to pay for it, but with the 6200 going for $35-50...
C: the PCI bus itself; I can almost feel my 6200 being held back by the PCI bus when running tests, I seriously doubt any more performance could be squeezed from it meaning you should definitely save your money on a less expensive PCI card (or even save it to upgrade your motherboard to get PCI-e, or even AGP...)
256MB is nice but for the most part PCI cards have been way too underpowered to require that much memory (which is why the 128MB 6200 can be one of the best PCI video cards despite an apparent lack of memory)
3DFuzion PCI GeForce 6200: $39 @ tigerdirect