You're best off building your own. If you can't do it (it's easy, seriously), the get someone to custom PC build for you. I'll provide some components;
CPU; i5-4670K. People will tell you to get i7, don't. It's a waste. i7 is just i5 with hyperthreading and anyone not doing video editing or image rendering does not need i7.
GPU; NVIDIA GTX770 or AMD Radeon 280X. You can settle for a 760, but don't get a 270X.
Motherboard; Asus Sabertooth, MSI Gaming GD5, Gigabyte UD5, or any motherboard within the $100-200 range will do just fine
PSU; Bronze efficiency and 600 watts is fine. Antec, Corsair and CoolerMaster are good brands
RAM; 8GB will do you fine, don't listen to others, RAM is one of the least important components. Go for DDR3-1600 OR 1866 but don't expect a huge performance increase for a DDR3-3000. Not worth it.
