Good location
Stayed at the Washington Hilton for a night last week. The hotel is well-located between Dupont Circle and Adams Morgan and Kalorama. Very walkable. If you're toting heavy bags, use the Woodley Park or Columbia Heights metro stops on your way to the hotel, since those walks are mostly flat or down-hill (the Dupont Circle stop would involve having to walk up-hill for a little bit).
Had dinner at the hotel bar and the food was decent, the liquour was better, and the service was superb. 
The room was very spacious and comfortable, and had a great view of downtown DC. Had the Washington Monument lined up with my window and could watch the planes line up to land at National airport. Very pretty.
Would stay there again in a heartbeat.