I built this rig for use at the office for 3D modeling and occasional code compiling.
I haven't overclocked yet but mostly because I haven't had the need to. Default clock speed on the 5820k crushes everything I throw at it.
The Silverstone TJ08B and Noctua NH-D14 are incredibly quiet even under "load". I put "load" in quotes because it is actually pretty hard to stress the system as I haven't done full stress test yet. The Corsair 650W is quiet as well because most of the time it can passively cool itself without having to turn on the fan.
If you want native graphics support for 3D CAD you don't have a whole lot of options for graphics cards, but the W5100 seems to get the job done.
The build itself was quite easy as the TJ08B has plenty of headroom for the Noctua. I took out the bottom HDD bay and mounted a SSD directly which makes cabling pretty straight forward. The TJ08B also has an isolated PSU in the top back of the chassis which is quite nice for airflow but makes initial assembly a bit tricky. You basically have to take off all the sides and top of the case but it is around a dozen screws in total, not a big task if you just pay attention. The W5100 has no issue fitting inside the case. A larger consumer graphics card would also fit easily if the HDD drive bay was removed (as I did). It might be able to fit in the 1st PCIe slot but the Noctua NH-D14 is very close to the 1st PCIe slot so I wouldn't recommend this. On some motherboards, PCIe slots higher than 1 don't support 16 lanes of PCIe so make sure you account for this in your MB selection.
Total cost of the rig was ~$1800 (Oct 2014). Considering the W5100 is $500 the build could be replicated quite easy on consumer grade hardware for around $1250 (including fancy DDR4 RAM) or probably closer to $1000 without the DDR4.