Hello,
This a difficult question to answer as none of them are "better overall"; it depends on your usage but I will try to answer anyway.
If you were a gamer and wished for the best performance in a game the i7-4960x may be what you are looking for but it is extreme overkill; you would only need something like a i5 4670k.
If you were looking to be doing a lot of multitasking or something that required the usage of a lot of cores at once then the the AMD FX-8120 might be the best.
If you were to be doing heavy video editing or 3D rendering then the i7-4760X would be useful due to its hyperthreading technology.
The Intel Xeon depends on which Xeon processor your choose. There are some with 12 cores like the E5-4657L v2 which is useful for servers but not so much for general usage. There are others with 4 cores like E5-2407 v2 which would be better for overall usage but in the end pointless; they have low clock speed compared to an i5 for the same price.
Overall the best processor for the price and if you wanted it for general usage would be the AMD FX-8120, but that would not be as good as mid-high end i5 processor but the AMD would still suit your the average person needs but with a lot of money wasted on the 8 cores.
Thanks for reading,
Nxl8