Gainesville is conveniently near 66, about 30 minutes from DC if no traffic. It has more space than DC, since its on the outlier of the suburbs. Lots of traffic comes up from Culpeper and locations in between.
Because some of the peripheral areas are still in development, its a nice place to get a larger beautiful space for a scenic lawn. Here is an example of a home in a be http://steadfastinc.com/patios-gainesville-va The closest mall is in Manassas, but Gainesville a very nice huge outdoor shopping village, which also includes Target and other big box stores.
Its right above Fauquier County, which is fiercely against development, so for a long time to come, you will have access to country roads and DC scenery. Best of both.