Does it have to be Nvidia? As a single card I find Radeon solutions within your budget generally have better performances. Their firmware support is no as good though and crossfire support sucks so if you want upgrade to 2 GPU later on than stick with NVIDIA.
One of the best thing about the 460 is its SLI performance so if you are thinking about eventually adding a second GPU on your board, make sure it has enough space to accomodation the neccessary PCI slots you'll need!
If you have no intention of ever getting the second card, there are cheaper Radeon solutions seems more beneficial, you'll also probably save money by optioning an AMD CPU/Board combo, they're usually cheaper and at your budget, not much difference in performance.
Good luck on your purchase.
