@ritwickgupta: I suggest you go through this article.
http://www.anandtech.com/video/showdoc.aspx?i=2717&p=1
7600GT is better than 6800GS. It was not available that time in february, otherwise I would have bought it.
As of now, there are no DX 10 cards around. You have to wait until the Geforce 8 series/x2xxx series cards come out.