The GTX680 just came out at $499.99, although it is now sold out most places. It outperforms the 7970, so at $550 a 7970 it isn't really a good buy unless they lower it to about $449 or less. The GTX680 supports 4 displays, 1 per output. It would outperform your crossfire setup by quite a bit. I believe with AA turned on at 1080P it performs slightly under a GTX590 or AMD 6990.
yeah ok thanks. here in the uk they still have some stock was thinking more along the line of the evga one? its roughly the same price as the 7970 around £420-£480 either one. I did a reference bench to the TH review of Crysis 2 @ 1920x1080 on ultra DX11 the GTX680 scores 69.7fps and my current crossfire setup manages 57.8fps, a 20.59% boost from a single card... impressive.