It really depends, if you have high workload a big CPU with high clock and more threads is better then big gpu for example.
For gaming on full HD (1080p) a single gpu is more then enough and sometimes even better (not from a fps point mind you) because dual GPU will always have micro stutter that are noticeable.
If you want to have a future proof PC you should consider getting a Intel CPU with HT (either Haswell-E or Refresh) because i am pretty sure we will see games with higher CPU (more cores/threads) demand, because of the new console generation.
something like this
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel Core i7-4790K 4.0GHz Quad-Core Processor (£248.34 @ Aria PC)
CPU Cooler: Corsair H100i 77.0 CFM Liquid CPU Cooler (£78.98 @ Amazon UK)
Motherboard: ASRock Z97 EXTREME4 ATX LGA1150 Motherboard (£104.36 @ Scan.co.uk)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1866 Memory (£60.77 @ Ebuyer)
Memory: G.Skill Ripjaws X Series 8GB (2 x 4GB) DDR3-1866 Memory (£60.77 @ Ebuyer)
Video Card: EVGA GeForce GTX 970 4GB Superclocked ACX Video Card (£286.76 @ Scan.co.uk)
Total: £839.98
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-09-24 14:56 BST+0100
Note, those parts are picked because you want to Overclock, if you don't need/want to OC you can also pick a
Xeon 1231 v3 and cheaper ram, i recommend G.Skill thou, good experience with them also EVGA > all other manufacturers
.
I choose a 970 simply because you pay 200 pound sterling (£ prices are insane btw) for only 10% more performance, really.
http://www.tomshardware.com/reviews/...l,3941-16.html
just skip to summary.