Just get a i5-4670k. Its more than enough for gaming cause gaming mostly relies on gpu not cpu. And that i5-4670k is more than enough. Don't look at those requirements of watch dogs, cause an i5 will still max out that game. Though its your choice.
Here's my recommendation:
ASRock z87 fatality killer motherboard(very good mobo and also preety cheap and support oc preety well cause i'm using it)
8gb 1600/1866(recommended) ram
gtx 650ti boost, cause same price 750ti but performs better and most notably supports sli( will give you almost like a gtx 680 performance with much less cost)
and a good 650w psu
Hope i helped