My honest opinion would be for you is to sell the 2 7770 and get a single 7950. There's never a guarantee that CF would work with no issue especially since you're talking about future proof (which I don't necessarily believe in the term...ah well). One card is always more optimized and I don't see things change in the short term. A single 7950 is also twice as fast as 2 7770s and you'll get 3GB VRAM vs 1GB effective VRAM. Plus, 7950 are well known as a great overclocking card as well. With a couple tweaks, you can get around the performance of a GTX680.