You also mentioned (in a follow-up) Prince William County. Your money absolutely will go farther there. However, some areas of Prince William have been very hard hit by the collapse of the subprime market--lots of foreclosures and short sales in some pockets of the county.
Your price range does limit you somewhat--sticker shock is not uncommon for people buying houses in Northern Virginia. I ran a search on the MRIS for all single family houses in Fairfax County under $475,000 (assuming there's some price flexibility on the seller's part), minimum of 4 beds/2 baths, built after 1985. (There are lots more if you go back a few more years.) There are 32 currently on the market.
Same search in Loudoun County came up with 159 listings. Same search in Prince William County came up with 766 listings. I tightened the parameters in Prince William to minimum 5 bed/2 bath, built after 1999, under $450,000, and came up with 84. I randomly looked at some, and the first 7 I checked were short sales or REOs. There were some nice ones there.
So, you really have to weigh nice neighborhood/horrendous commute (Loudoun County), better values/more selection/somewhat better commute (Prince William), or better commute/more expensive/less selection (Fairfax County).
If I can help you further, just let me know.
If you'd like information on Loudoun County, check out my real estate blogs - LoudounStats (dot com) and LoudounForeclosures (dot com). Check out the "Buyer Resources" category on the left hand side of Loudoun Stats (link below). There are links to neighborhood info, HOAs, school, crime and other information including sites and companies that provide demographics on the county. It may come in handy to you.
Welcome to the area and let me know if I can be of assistance.
I recently left Northern Virginia and moved further south to the Fredericksburg Area. Unfortunately, the market is expensive and time is money. The areas that you are looking at will give you more for your money but the commute will be brutal.