My vote goes here too. Overclock both and you'll have a beastly little system on your hands!
me too i5 4670k + GTX 780
I think it really depends on what you will do to your PC You have to prioritize your usage on your PC if Gaming is the main purpose go for i5 4670k + GTX 780 as hyper-threading in i7 doesn't benefit gaming performance if you will do video editing or photoshop more over gaming then i7 4770k + GTX 770 4GB maybe a better option.
For gaming the 4670K + Gtx780 will be a much faster system. You should plan to overclock the 4670K though or it's a waste of money.
The 4670K is faster than anything AMD currently makes, period.
4670k and 780. FX 8320 only if you plan to record your gaming and do any kind of video editing of your gaming. The dark horse here, if not wanting to overclock, is an E3 1230 v3. Costs a bit more than a 4670k, but cost can be offset by less expensive motherboard than a 4670k would need.