I recently stayed at several hotels in the Washington DC area. In general, hotels in this area are expensive (compared to other parts of the country) and available rooms are difficult to find unless you book well in advance. Since I travel on very short notice, booking in advance does not work for me and I have to rely on what's available at the moment.
The Hampton Inn Fairfax, VA proved to be decently priced and very nice hotel. The lady at the front desk was very nice and welcoming. The room was spacious, very clean and modern - with flat screen TV, mini-fridge, coffee-maker, etc. Lots of TV channels to chose from.
My rate included free breakfast, which was pretty good. There is a restaurant right next to the hotel. 7/11 is also conveniently located right next door.
Overall, very pleasant experience. I would stay at the same hotel next time I am in the area.