If you want absolute top performance, go Intel. If you want something like 80% of the performance of Intel's top of the line right now for a lot less money, go AMD.
Also, AMD changes their CPU sockets less often. With Intel, you'll quickly be stuck without an upgrade path on your motherboard because Intel's next line of CPUs won't fit the socket any more. AMD tends to keep the same socket for a few years. And when they do change sockets, AMD usually continue making versions of their newer CPUs that will work with older sockets. Meanwhile, Intel is notorious for not doing that. Forcing you to buy a new mobo along the the CPU.
Intel's Hyper-Threading is only good for productivity work, not gaming. Even then, most people don't even bother with it and go for the version of the i5 without Hyper-Threading.
If you do decide to go AMD, I strongly recommend getting any of the new 3-series FX chips (Piledriver) and avoiding the 1-series (Bulldozer). The 8350, 8320, 8300, 6300, 4320, 4300 are the ones to get.