tiggerlover We moved from there 2 years ago. Sadly, the housing is even worse than when we left.
We bought a 4BR/3.5ba townhouse in summer 1999 for $167,715. Sold it summer 2002 for $249,950....50% profit. The last one to sell in that development went for $375,000 in September.
That said, your income should be higher there (I know our BAH was...and it actually kept up!). If he's working for the FEDs he'll get locality pay, too. Keep that in mind.
We lived in Lake Ridge, VA, which is in Prince William County. We LOVED our neighborhood (a HUGE planned development...really a mini-town) and how close we were to DC, yet far enough away from most of the hassles. Lake Ridge has everything from small rental apts. to million-dollar homes, and everything in between. Schools are pretty good, although Fairfax county is rated higher. BUT, you'll pay at least $100,000 more for the same thing in Fairfax county just because it's closer and it's Fairfax. Our developement was on the river separating PW county from Fairfax....we could throw a rock and hit Fairfax, but we got our townhouse for $100K less.
"Reasonable commute" in that area means different things to different people. DH worked with some people who commuted 2 hours each way from WV. I kid you not. Out there they could afford land and mini-mansions for what we were paying for a townhouse, so they sucked it up and dealt with the commute. We weren't willing... One hour plus commutes are the norm. We were lucky...DH worked near Ft. Belvoir so he drove 16 miles to work (and at odd hours so he didn't have traffic very often), but school at Andrews twice a week ran him 38 miles each way.
We were exactly half-way between Ft. Belvoir and Quantico, so I used both commissaries, and just planned according to traffic flow.

You'll still have benefits, so that's something to think about....not a deal breaker or maker, but nice to know.
Good luck on the job/house hunt!!!