True, but if you can deal with the commute (assuming that you would be working in Fairfax/Arlington/D.C.), you could afford to live in Stafford or Prince William counties or The City of Fredericksburg.
We moved from Fairfax county and it has saved us alot of money. Daycare costs are half of what we used to pay. Gas is about .20 cents a gallon cheaper. Housing is cheaper too...but it is on the rise.
There are more companies relocating to the Fredericksburg area these days too.
My wife works in Falls Church and was looking for a job closer to home (Fredericksburg) and thought that she would have to take a cut in pay. She ended up finding a company in south Stafford county that not only hired her (the guy wrote her offer letter during her interview!), but is paying her more. This is for an accounting job (she has an AA degree) but there are alot of IT jobs in the area too...but alot of them require a clearance of some sort.