There is a bunch of different talk about what is more important RAM MHz or RAM timings. I have tried both sacrificing timings for more MHz, and sacrificing MHz for timings. The results surprised me. If you have lower timings, you have better overall system speed. That being said, if you can have both, you're doing better yet.
To choose the other parts of your computer system, start with the parts on the right column, the parts here will correspond to those pieces to make a system.
TIP! The number on the RAM 8500, 6400 or 16000 refers to the speed, if you divide that number by 8 you'll get the MHz speed the RAM runs at.
Corsair Dominator CMD16GX3M2A1600C9 16GB - Will work with all Motherboards, a little lower on the MHz but the timings make up for it. For a video editing computer buy 2 kits.
Kingston Hyper X Beast KHX21C11T3K2/16X 16GB - Will work with all Motherboards, faster MHz speed but a little higher timings. For a video editing computer buy 2 kits.
Here the main focus for me is quality. Reviews end up being the first thing I look at. Next, I want speed or timings. If I can have them, I'll take both, but to some degree it seems to be a compromise. After that, I just make sure it will fit on and is supported by the motherboard. Lastly, if I'm adding an aftermarket CPU cooler, I make sure that the two will fit. Usually you can find this on the CPU cooler manufacturer website.