If you want to limit your GPU choice in the limit of 750 Ti performance, I have 3 suggestions.
Best choice: Get an AMD Ahtlon 860K and an AMD 265. You will probably be able to get it for the same amount of money as an 750 Ti/FX6300 and it will net you better performance.
2nd best choice: The 750 Ti will do just fine with most CPUs really. If you really want to get the 750 Ti (though for the best performance, you're better of with the 265), an 860K will also do just fine. The 750 Ti being a low end GPU and being the main reason for performance bottnecking in games, the 860K will be just fine.
3rd best choice: If you can find a 260X for a quantifiable smaller amount than a 750 Ti, it's also a good setup in combination with a 860K.
PS: Clock for clock, the 860K is some 15% faster than the FX 6300. So in games using only 4 threads properly, the higher performance of the 860K cores will outperform the 6300 cores.
PPS: The 860K comes with a newer motherboard chipset, better featured than the chipset the FX 6300 uses. So that's nice.