This should probably be in new builds and planning but because you are new, thought you should know.
Second what are you planning on doing with this build? Gaming, Content Creation or General use or a little bit of everything?
For general use the best CPUs would be AMD Athlon X4 860K, Intel Pentium G3460, Intel i3 4150
For gaming (Not OCing [Overclocking]) the best ones would be Intel i5 4430 or 4430
For content creation you'd probably be best going with like an Intel Xeon E3-1220 v3.
Though if you're sold on getting an FX series CPU then probably you'd be better off with and FX 8320 and R9 280X and as someone mentioned earlier 990FX is the chipset you should try to stick to.
(Note - I was price checking on the US Intel and AMD site so yeah prices are probably going to be different.)
