I had my mind set on the 680 for awhile now but with the release of the 670 I am wondering if I will be just as happy with the 670. From most of the benchmarks I read I see a 1-5 fps difference. I've also read the 680 is 20% more powerful. In terms of longevity of running the upcoming games on max settings, do you think the 670 will hold out about as long as the 680? So my question is the 680 worth the extra $100?