I have a coworker trying to sell two 7900GTs for $350. I'm trying to explain to him that there is no way they are worth that much. $350 will buy a 5850 which would smoke that setup without even trying. I'm not sure what two 7800GTXs in SLI can do, but I'm sure a single 8800GT could probably match or beat it.
Your best bet it to find a GTS250, GTX260, or 4850/5750/5770. This depends on your preferences and budget. I wouldn't bother setting up SLI on the 7800GTX.
Tnx getting a 9800 GTX card about 100 USD figure specs will be much better