$1200-1400 PC Build: CAD+rendering/gaming

Hi all!

Long time reader, first time builder. I am looking to spend between 1200-1400.

APPROXIMATE PURCHASE DATE: in three weeks

BUDGET RANGE: $1200-1400 USD

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: 3D CAD (Solidworks/Alias Studio), gaming, general browsing/movies

PARTS NOT REQUIRED: keyboard, mouse, speakers, monitor

PREFERRED WEBSITE(S) FOR PARTS: Newegg (or any other reputable US company)

COUNTRY OF ORIGIN: United States

PARTS PREFERENCES: whichever is recommended

OVERCLOCKING: maybe

SLI OR CROSSFIRE: only if it helps

MONITOR RESOLUTION: 1900x1200

ADDITIONAL COMMENTS: I'd like a case that is professional and isn't showy (more streamlined if possible). I've looked through so many different cad/gaming builds but they all seem to be unique solutions and different enough from mine. Basically, what I'd like to accomplish with my computer is build a Solidworks model, render it, take a break and play a game (like Battlefield Bad Company 2), maybe watch a movie, then go back to work. I know this seems like A LOT and perhaps my budget is TOO small but any help is appreciated! Thanks!