My computer build is:
CPU: i7-4770k (running at 3.5GHz stock, I don’t OC).
GPU: GTX Titan.
RAM: 16GB. (The max for Windows 7 Home Premium).
I won the PC in a competition run on the PC Gamer UK website, with the prize by ZooStorm*. It is a thing of beauty. 
*I.e. I wouldn’t necessarily recommend a Titan if you were paying for it yourself.