nikol1000

1, HD7970 is equally performing to the 770
2, New consoles use 8-core APUs so games will be more optimized for octa-cores.

Nope, that PSU is certified only up to 30°C, which is very easy to exceed, so if you run 2 7970s in the future (very hot cards), your PSU might not supply enough power, so it will just crash. The TX750M is certified up to 50°C, I can't think of exceeding that limit in the Arc Midi R2.

I came up with this build, 230DKK over:
http://www.cinemagic.dk/shop/amd-black-edition-281500p.html
http://www.cinemagic.dk/shop/gigabyte-ga-990fxa-ud3-87032p.html
http://www.cinemagic.dk/shop/kingston-hyperx-blu-299943p.html
http://www.cinemagic.dk/shop/corsair-tx750m-750-288062p.html
http://www.cinemagic.dk/shop/msi-r7970-tf-321943p.html
http://www.cinemagic.dk/shop/seagate-barracuda-7200-125569p.html
http://www.cinemagic.dk/shop/fractal-design-arc-307794p.html
http://www.cinemagic.dk/shop/kingston-ssdnow-v300-289801p.html
http://www.cinemagic.dk/shop/cooler-master-hyper-179671p.html
 
Should be awesome for gaming, you might also put out an awesome OC, case has a lot of airflow, PSU can handle even a second 7970, I also created a nice color scheme of black/metal which goes nice with the case.

Asus geforce gtx 780 3gb 4649kr
Gigabyte ga 970a-d3p socket am3+ 639kr
Seagate Barracuda 1tb 469kr
AMD Fx 8350 1399kr
XFX Proseries XXX edition 650w 649kr
Corsair Vengance 8gb 1600MHz 679kr
Total cost is 8484 kr
 
Prices are taken from Komplett.dk
You're welcome

The build pretty much outperforms your original list in every way. This is Cinemagic.dk  which you said you were shopping from.