my personal suggestion is the MSI Gaming 4G GTX 970. It has mil spec components 6 phase power on the GPU and 2 phase on the memory. Stock I blieve is 4+1. The Gigabyte G1 is also a nice card, but no where can I find what phase power it uses for the memory, but it is 6 phase on the GPU. So for GPU overclocking they will probably be in the same ball park. I just like the milspec components. The Gigabyte is one long card so take that into consideration. It also has the best output options. I believe HDMI, 3 DP, and 2 DVI. The MSI is 2 DVI, 1 HDMI, and 1 DP. So if you are planning for more than one display think that through.
I am running 2 MSI gtx970's now and they run like a dream. The stock fan profile is really good even when i OC...