https://www.ekwb.com/custom-loop-configurator/
Use this. They currently have the BEST cpu cooler on the market( EK supremacy EVO). Pick your case, cpu, mobo, and video card, and it will recommend a setup.
you can modify the selections to get more cooling capability for overclocking better.
We recommend noty to use pastels in your loop, and to use primochill flex tubing for color instead. This makes maintenance much easier.
As for the rest, you need to provide a MAX budget you can handle(within reason to one person could be $40. to another, $900), as well as your pc specs that will be watercooled. This includes the case, cpu, mobo, ram, video card, ssd, like in my signature,
concerning mobo blocks and ram coolers, those are purely asthetic, and won't provide much, if ANY difference over the passive heat sinks/heat spreaders.
As for which radiators to use: EKWB has very high quality ones, but they generally are on the more expensive side of things. They are quality though, and the more rad space you have, the cooler and quieter the system will be.
If you have a case with tube passthroughs, you could opt for very large rads, like this one, but they are very expensive, but, VERY good.
http://www.aquatuning.us/water-cool...kQBis5xuFtKS_vsxLH9eiOe5Kt_XnfDZY2xoCBuXw_wcB
But know that once you go with external rads, It is a pain to move your pc, because if you don't move both, you risk causing leaks from tugging on the tubes.