I will use sli once the card that I have is lowered alot in price. Then you can ugrade your pc without bying a completely new card.

As for SLI needing 2 cards. It's true but theire is a loophole. the command set of sli has been use also to put two gpu chips on one card. This was actually a clever trick by some producers.
Quote

If two graphics cards in one system are too expensive or simply not fast enough, Gigabyte's new 3D1 board may be worth a serious look. Sources told Tom's Hardware Guide, that the company prepares to launch a dual-GPU card Friday, saying that it will "revise the VGA performance ranking".


1The card integrates two Nvidia GeForce 6600 GT graphics processors and is the first 6600 GT card on the market to offer a total of 256 MByte DDR 3 memory and 256 Mbit of memory bandwidth, according to the manufacturer. The card is cooled by two on-board fans.

The 3D1's two processors communicate through Nvidia's SLI interface and achieved 14,293 points in 3DMark2003, sources at Gigabyte said. This would not only be almost twice the performance of a regular 6600 GT card, but also more than ATI's Radeon X850 XT Platinum Edition, which achieved in Gigabyte's test environment 13,271 points and Nvidia's GeForce 6800 Ultra, which posted 12,680 points.


http://www.tgdaily.com/2004/12/16/gigabyte_creates_dual/index.html

December 16, 2004 16:58

Not in the mood for cheese?
That excuse has more holes than a slice this fine Gorgombert!