What cpu i would want for building a system

You will want more cores for encoding and for other kinds of heavy work. Gaming can also benefit from have 4 cores or more but there aren't many situations where they are needed

For non gaming you will need something like i7-2600k which is hyperthreaded.

Not only the CPU -- but the GPU.

Using a $160 workstation card can improve elements of editing and encoding.

A FirePro V4900 with an FX-8120 would be a better choice than simply an i7-2600.

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Yeah Wisecracker is right. Don't neglect the GPU