The Ram you have listed I believe is an 8gb x 1 set. You are going to want a 4gb x 2 set to take advantage of dual-channel memory. I also found a PSU that is rated as a tier 2b(meaning it's good enough to suggest it for your pc) that is only 2340. Also there is a cheaper case by Antec that I'd recommend as well.
Judging by the games you want to play, I think you'd be better off staying with at least the 7870. The drop in performance with the 7850 will hurt too much I think. Depending on the pricing, you might actually be better off going with an AMD Cpu, I'm going to check pricing.
Ok, even with an AMD cpu, you won't be able to go up to the 7950 GPU. After reading on the differences between the h77 chipset and b75, I'm going to recommend the b75. Only supports 16gb of ram(which is fine, you only need 8gb atm) and only has one pci-e slot(which is fine too, since you are only buying one card right now, and when you might want a better one in the future, just buy a new one instead of trying to crossfire).
Same intel cpu for 7500, motherboard is 2800:
http://dynaquestpc.com/index.php/gigabyte-ga-b75m-d3v-lga1155-motherboard.html , Ram is 2240 for dual-channel ram:
http://dynaquestpc.com/index.php/gskill-sniper-8gb-4gbx2-ddr3-1600-pc3-12800-cl9-memory-ram-f312800cl9d-8gbsr2.html , PSU is 2340 for something I'd recommend
http://dynaquestpc.com/index.php/enermax-naxn-82-series-550w-80plus-bronze-power-supply.html , and the same video card as what I said earlier, and same case. That NZXT case has gotten several reviews, and a few of the sites I read really like it for the price. All together the build comes to P27080. Pretty decent build for todays games and it would do you just fine.