My advice:
1) I would grab a small SSD for windows (60-100gb) just the cheapest you can find (this is your windows drive).
Then a regular or hybrid drive at 500gb-1tb (this is where you keep all your installed games on ect).
2) Id probably save a few $ and get a i5-6400/i5-6500 instead.
3) I wouldnt buy super expensive ram, get the cheapest ones rated at the values you need.
If you dont need 2666mhz dont buy them. The gain in performance is so damn small, and sometimes the differnce in ram prices are pretty big.
4) Sound card? why? the onboard ones usually so good you wont be able to spot any differnce between them and the discrete sound cards you can buy for pci. Its a waste of money imo.
5) Make sure the power supply is a high rated one, its one of those components you really shouldnt be cheap on.
6) Its convient the RX 480 is soon out, Id get one of those to go with this PC your building.
Their supposed to be really good value.
If your looking at keeping it under 700£ that shouldnt be a issue.
Its alot of money and as long as you spend it wisely you can build a pretty darn good PC outta it.
(hint : skip the sound card, use the onboard, go small&cheap on the SSD, and ram)