Depends what you want to do with the machine.
For games get the fx with the dedicated graphics card (although maybe look at some other cards, the 750 is a bit pricey for its speed, gtx 660, or the r7 260x or r7 265 are faster and better perf per $).
If the machine is for work, the i5 is a better general use processor and the hd 4600 is sufficient for light tasks.