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.
The parts list posted by C12Friedman looks good although I would go with a Gigabyte GTX 670. It is a great card and priced much better at $379.99 at Newegg plus Newegg has a $20 mail in rebate right now putting the card at $359.99. The Asus GTX 670 is a good card I just do not think it is worth the extra $60+ for it. I would keep the Z77 based motherboard and up your CPU to a i5 3570K with the money saved on the lower priced GPU.
I like Bryon's suggestion for the 3570k and Z77 mobo I simply built mine around your chosen CPU
I also forgot to point out that on my build the ram is done in a kit of two which enables dual-channel operation (preferred)