Sorry if I am getting to this post really late to the game...
I bought a townhouse in Silver Spring, MD last February, when I started at NR. A 3BR about 1 mile from the Wheaton metro stop which I take to work everyday. I pay about 90% of my BAH (w/dependents) toward the mortgage/insurance/taxes. Almost felt bad for "stealing" the house from the woman in such a down market; she had to sell it to me for less than what she bought if for 6 years earlier. I imagine there are still a lot of good deals to be had in the market. I couldnt comment too much on renting, I didnt bother looking much into rental units, but I know that getting any kind of 3/4 BR townhouse is going to be expensive.
I like Silver Spring a lot, its one of the most culturally diverse areas of the nation. Montgomery county is pretty affluent as well, it has some great schools and between Bethesda, Rockville and Silver Spring you can find pretty much anything you want. That said, the vast majority of new hires at NR do live in the Fairfax area.