Which graphic card to buy
Those are all very similar in terms of performance. I'd take the EVGA GeForce GTX 970, but other people will tell you something else.

One recommendation: Samsung SSDs are severely overpriced. People still buy them because Samsung has a good reputation (basically it's the same as buying a Mac for no other reason than 'all the graphics people have one'), but you won't notice any difference in any aspect between a Samsung and, say, a Crucial SSD. I recently bought the Crucial BX100 and I'm very content with it. Same price, but twice as much storage capacity.

Also, if you're getting a good GPU anyway, I would consider something like the lntel XEON E3-1231V3 over the i7 CPU, since you don't really need the inbuilt graphics unit of the latter.