there's a course in lorton (which is about 25 min away) its called laurel hills and its really nice... It's public but its well kept and there is always a cartpath only rule, so the conditions are always nice. If you don't mind a spending a little allowance money, laurel hills priovides variety and some challenging play.

cchoi31 mentioned fairfax national. thats a pretty good course too... it's got some pretty narrow fairways, but its really flat. once you get used to the fairways, it gets kinda boring