Scott,
I would recommend getting a SSD just for your OS and CAD and other editing programs and use ordinary HDD for storage. From what Bill said i also recommend a 1000watt power supply, corsair produces very good PSU's.
For video card i recommend a workstation card. Here's a good one:
http://www.newegg.com/Product/Produc...82E16814133258
Its nice for rendering and you dont have to deal with priority crap you get with two cards. It supports up to 4 monitors.
For Memory I recommend the GSKILL Ripjaws. They work perfectly with the 6cores and come in pairs of 4gb totaling 8gb per pair. Get atleast 8gb or up. You're gonna need a lot of memory for CAD and video editing and its gonna help alot on multi tasking.
Hope this helps and good luck!