1. You need a motherboard.
Pick any lga2011 motherboard. There is no need for the most expensive.
Here is one:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131801
2. You need ram.
You want documented ram compatibility. If you should ever have a problem, you want supported ram.
Otherwise, you risk a finger pointing battle between the ram and motherboard support sites, claiming "not my problem".
One place to check is your motherboards web site.
Look for the ram QVL list. It lists all of the ram kits that have been tested with that particular motherboard.
Sometimes the QVL list is not updated after the motherboard is released.
For more current info, go to a ram vendor's web site and access their ram selection configurator.
Enter your motherboard, and you will get a list of compatible ram kits.
While today's motherboards are more tolerant of different ram, it makes sense to buy ram that is known to work and is supported.
More ram is better. With your budget, buy the most your motherboard can handle. Ram speed is secondary.
3. If your apps can use the CUDA capabilities of Nvidia, then buy a Nvidia card with a fair number of CUDA cores.
For gaming on a single monitor, a GTX780ti is as good as it gets. Only if you will be gaming on triple monitors might dual cards be needed.
4. Your psu needs really are minimal. They are determined by the graphics card. A 650w psu can handle even the strongest of graphics cards. I might suggest the Seasonic X650
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151088
Nothing wrong with 750w either.
5. A case is a personal thing. Lian-li makes very good quality cases.
If you want quiet, look at this list:
http://www.silentpcreview.com/article75-page5.html
6. I strongly urge you to use a SSD for the "C" drive. I will never again build without one.
It makes everything you do much quicker.
A one hour windows update takes 15 minutes. Files open instantly.
Look for a 240gb Samsung evo. Use your hard drive for storage and workfiles.