I'd go with the Xeon and GTX 760. The 1245v2 is for socket 1155; why not go for the latest 1150 socket with a 1230v3?
I don't recommend AMD or personally, overclocking either. I wouldn't expect to gain much from an overclock, it's not that spectacular. You won't notice much difference from the GTX 760 and 770 either, according to Tom's Hardware GPU Hierarchy Chart.
Going with a Xeon and GTX 760 is the best route.
All the best.