Yeah I would say go with the 660ti since you really want Nvidia. However if you want to have a little more money then go with the 7870 black edition http://www.ple.com.au/ViewItem.aspx?InventoryItemID=609166&CategoryID=259 or you could even just go with the stock and save even more. The performance between the 660ti and 7870 black edition or ghz edition are fairly close.
either EVGA 660 Ti FTW sig 2, Asus 660 Ti Direct CU 2 whatever, Or grab a dual fan or tri-fan 7970 (Overclock insanity). I currently have a FTW sig 2 660 ti and I managed to push it to 1267 stable running crysis for an hour ( That's higher than most 680 clock speeds)