Which airport? If Dulles, I suggest picking one of the stops along the Orange Line. Vienna is the closet to Dulles but you may want to consider some of the next stops along the Orange Line.
I'll be driving to DC from Baltimore on Wed afternoon or early evening. Staying in DC until Thursday, probably have to leave mid/late morning. If I fly from Reagan Nat'l, I can probably stay a little later.
Actually, from Dulles Airport, there's a bus ( the Washington Flyer Coach, http://www.washfly.com/ )that goes to West Falls Church Metro on the ORANGE line