The X58 will support any video card that has the SLI connectors to use the SLI bridge on (see pictures for connector & bridge)


Some of the cards that can be used are:
All 500 series cards
All 400 series cards
All 200 series cards
All 9 series cards
8 series cards above the 8800GS
Please note that you have to use the 180.48 or above drivers to utilize SLI on the X58 motherboard.