If you want best possible card for your CPU at the moment, get GTX 1070. If it is too expensive, get: GTX 980ti > 980 > 970. BUT if you will get 980(ti) you will have to overclock your CPU (Yes, you can overclock Non-K Skylake CPUs) to 4.6 GHz. If you want you can wait for RX 480 (July-August) or for GTX 1060 (September)
If you want best possible card for your CPU at the moment, get GTX 1070. If it is too expensive, get: GTX 980ti > 980 > 970. BUT if you will get 980(ti) you will have to overclock your CPU (Yes, you can overclock Non-K Skylake CPUs) to 4.6 GHz. If you want you can wait for RX 480 (July-August) or for GTX 1060 (September)