Next Component in Need of an Upgrade in my Desktop

Hi,
I have a Gateway desktop computer that is about 3 ½ years old which I use predominantly for gaming. I recently updated the GPU from a GTX 560Ti to a GTX 970 which has made a huge difference in performance. I’m considering whether I should bother upgrading any other components and if so what should be next. The computer specs are as follows?

System Manufacturer: Gateway
System Model: FX6860
Processor: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz, 3401 Mhz, 4 Core(s), 8 Logical Processor(s)
Installed memory (RAM): 16.0GB DDR3 Memory
Graphics Card: EVGA GTX 970 4GB GDDR5 256-Bit
Hard Drive: 128GB Solid-State Drive + 2TB Hard Drive
System type: 64-bit Operating System
Operating System: Windows 7 Home Premium
Power Supply Unit (PSU): FSP 750W

For modern gaming, what should my next PC component upgrade be? More RAM, a new processor, a better PSU? Or based on my specs should my computer be able to handle most new games for a while to come and is not worth upgrading anymore? Just looking for some opinions and advice. Thanks!

Next Component in Need of an Upgrade in my Desktop