My recommendation would be:
1 - Get a z77 motherboard. There the same price as z68 and have minor upgrades over z68 here and there. Its newer tech anyway so might as well.
2 - While its not a big deal, I would get the 3570K over the 2500K. Again its not a big upgrade and the price is the same but paired with a z77 board you get native PCI-e 3.0 lanes, uses less power and has a better iGPU
3 - GPU, I would not recommend getting an AMD GPU this generation. NVIDIA has them beat out in pretty much every aspect this time around. Granted the 7970 is a powerful card. For the money you can get a better bang for the buck card such at the GTX 670 FTW edition. Factory OC'd 670 which performs at GTX 680 speeds. The Kepler cards also use less power than their AMD counterparts.
4- The case, $180 is a huge waste of money for a case. You can get a case for around $65 that will be just as good. The extra savings could also go elsewhere, such as an SSD which I was going to recommend.
5- SSD. With the savings you'll have from a case change, that money can get you a 128GB SSD. Put your OS and most used programs on it and the rest on the mechincal drive. The speed difference is huge. Booting up alone takes a few seconds.