SLI Graphics, or Single graphics with Physics?

If you really want to spend your money, then get the SLI.

Not all games/applications need Physics card and not much games/applications support Physics card.

I wouldn't do either. Physics cards are a waste for now. There are only a couple of games that barely support it right now. IMO it's pretty pointless SLIing lowend GPUs. Why not take that +-$300 ($200 PPU $100GPU) and get a better GPU and more RAM (if you have less than 1GB). Either one of these would be much better than SLIed 7300GTs.

http://www.newegg.com/Product/Product.asp?Item=N82E1681...
http://www.newegg.com/Product/Product.asp?Item=N82E1681...

Cool, thx man! Whats the performance diff between the 1950pro and the 1900XT? Will it also help if I upgrade my CPU to a 3800+ or maybe a dual core?

The X1900XT is faster than the X1950pro, but it's hard to beat the price/performance ratio of this...

http://www.newegg.com/Product/Product.asp?Item=N82E1681...

This is one hell of a deal Cleeve found on Newegg.

EDIT: Link didn't work...now it does, but now Out Of Stcok