There are quite a few problems with that build. Firstly, You have a non-k CPU with a Z77 motherboard. If you want to overclock, you need a CPU with the "k" designation, such as the i5 3570k. If you don't want to overclock, you want to use a H77 motherboard, as they are significantly cheaper.
Secondly, you want to use two sticks of 4 GB RAM whenever possible, as the result is slightly more effective than a single stick of 8 GB RAM.
Thirdly, to my understanding one should always avoid Thermaltake PSUs. I've heard nothing but bad things about them. I would advise switching to an Antec, Corsair, or SeaSonic.
Lastly, although this is definitely subjective, most folks on this forum won't advocate using 680s. The 670 FTW is only slightly less powerful and much cheaper, and the 7970 Ghz. outpreforms it at a roughly equal price.