You have to get one of the cards specifically labeled for use in a Macintosh. Currently, of the cards you listed, only the Radeon line ships with such a model. There are no off the shelf nVidia cards for the Mac yet. It is possible to use an old PC 3dfx Voodoo3 AGP card in the Mac, but the firmware on the card has to be reflashed with Mac-specific instructions. A complicated process. You're best off getting the Radeon card. The correct card can be acquired at most Mac online stores, including the Apple Store.