Have you even read what i wrote down. Im telling the OP to check what for programs he will be using and if they are GPU dependable. As far as gaming goes, a 7950 boost card will be better than a 660 ti.
http://www.hardwarecanucks.com/forum...review-19.html
I could imagine the better mem specs (384 bus vs 192, 3gb vs 2 gb) could also make a difference for rendering etc. But my main advice is to check the programs the OP will be using. If they favor nvidia get a nvidia card, otherwise it might a good idea to check out something from AMD in that price range which is a 7950.