What on earth are you using this computer for? If it's some serious blending get several computers and separate it between them Jesus H Christ.
If you're using it for gaming then all of this is really just not needed... 256Gb of RAM?? What the ever loving fuck? For a very VERY high end machine 32Gb is more than enough.
If you want a beast and you have money to burn. Spend about $2000, then just buy new models as they come out so you constantly have top of the line new shit. Not waste thousands on hardware that will be obsolete in a few years.
For videos, I'd go the Nerdcubed route. Get a fucking beast of a case, put all your important shit in one bit. That's for gaming and the likes. Then have a smaller server computer for uploading and rendering.