The most important bit is the hard drive and their setup. This is going to be the core of your experience using your computer. You want SSD(s), naturally. You dont want ones smaller then 250gb which should be your entry point. Depending on the size of usual projects you use- get 2x that amount. For example, your project files are 100 gb- get the 250gb model and so on. You may want to invest in the very expensive, but very fast versions of the SSDs- m.2.
You may want more than one. You may also want regular old HDDs for regular long term storage. Here, you want space not speed so get the one with the most terabytes. These are very cheap.
Now for speed of rendering you want as fast as CPU as you can get, which means Intel. The more cores the better. You want lots of RAM, 16gb to start with, you can always get more if you find yourself using most of it- easily checkable using task manager in windows.
The tricky question is what GPU and the answer depends on what software you'd be using. Are you using Adobe Premiere with Mercury Playback Engine? Are you using some other GPU driven render engine? If so get the aproprite GPU- most likely an nvidia GPU. If so I recommend GTX 960. It's as fast as Premiere will use and it supports CUDA has plenty of cores and is more than decent in games if you care about that.
If you don't care about MPE, GPU driven render engines in general nor about modern 3d games, you'll be fine with the GPU built in the modern Intel CPUs. Double check that that GPU can run the number of displays you have in mind in the specified resolutions and you're good to go. If you still want a discreet GPU, but don't care about the high end- get 750 ti. It's very power efficient and more than capable little GPU.