This is a personal question because it all depends on what you are
building, a gaming system or a working desktop or a system that will deal with a lot of animation, and what type of
benchmarks you are striving for. So, look at what you want to do with
your system and then from there, start researching the hardware that
best suites the job.
Also, something else you may consider. If
you have the money, but not all of it at once, but the top of the line
motherboard that you want, but, buy a cheaper CPU that will work with it and when you have the
money, then go for the top CPU that the motherboard can handle. It may
save you money in the long run, especially if the first chip you buy
works great for your current projects. Then, as your projects get more elaborate, go for the better hardware.