Nice build!
I'd only change a few things:
That RAM is a bit basic, and has a comparatively low clock speed at 1600MHz. For your purpose especially, I'd recommend going with higher clocked RAM as it can help cut down on render times.
The Cooler is very good for the price, but for a high-end build like this if you have the budget it would be better to go with something like the Noctua NH-D14.
I assume the SP series fans are for the cooler? You won't need them if you go with the noctua, the fans included do a great job.
Finally, are you certain that you won't be needing anymore than 250GB of storage? To my knowledge, CAD involves quite large files (I may be wrong, though.), and if you are gaming (Assuming you play most of the popular games right now.) as well then 250GB almost certainly won't enough. That is personal preference though, and is up to you as I don't know how much you really need.
As always, keep in mind that you will need a fresh copy of windows, and of MS Office too unless you use another office package like Google Docs. A windows installation on your old PC won't work with the new one, so keep that in mind too
.
Here are the prices of the components I mentioned (Using Australian PCPartPicker.):
PCPartPicker part list /
Price breakdown by merchant
CPU Cooler: Noctua NH-D14 65.0 CFM CPU Cooler ($99.00 @ CPL Online)
Memory: G.Skill Ares Series 16GB (2 x 8GB) DDR3-2400 Memory ($143.00 @ IJK)
Total: $242.00
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-09-19 00:10 AEST+1000