Building it yourself is not hard. It is in fact pretty easy if you know how to handle a screwdriver.
If you press the Overview tab at the top of the hardware forum, there is a drop down box with articles that may be of help.
Just one thing: Take your time. No need to rush.
I'm all in favor of building. I won't ever buy again. Too expensive, and little control over the exact parts used.
Personal preference... but I built a similar computer... with an 850w power supply
Search on something like (if the search is working today)
Harm power supply
to find a link to a calculator
How valuable is your time? I recently completed my build. Indded, they are not hard to assemble but it's getting all the components to play well together that can turn into a black hole. I enjoyed selecting, assembling and setting up my own PC. Not sure I would do it again. Something to be said for turn key system. Look here for something made just for editing. Eric and Scott are always contributing on this forum.