As a longtime DC area resident, I will agree with others that: (1) the better courses are outside the Beltway, often WAY outside the Beltway; (2) many are CCFAD venues; and, (3) conditions can go to hell during a hot, dry summer. #1 is true, however, to a great extent for the better country clubs such as Woodmont and Congressional in MD and Belle Haven and RTJ in VA.
With regard to the glut of CCFAD courses, thanks to our economic woes, there are reasonable deals to be had at some. Groupon, for instance, was offering a $49 round (that's pretty reasonable by DC standards) at new CCFAD 1757 Golf Club earlier this week. GolfNow.com offers discounts at several of the high-end courses, especially thsoe in VA.
As for courses worthy of a visit, I'd put the aforementioned Laurel Hill (which will host the 2013 US Public Links Am), Worthington Manor (regularly used as a US Open local qualifying site) and Whiskey Creek at the top of the list. Worthington, in particular, has very fast greens, many of which are severely sloped and which will be a hit with many GCA'ers. While it can be walked - and I've done it - the degree of difficulty on the front nine approaches that at Black Mesa, which I played recently. While there aren't too many hidden gems or legit bargains, Enterprise (near the Redskins stadium), Poolesville (flat fairways, but some interesting green complexes) and Andrews AFB-West are ones to consider.
P.S. - Forget about East Potomac Park unless you enjoy a 6-hour round!