You can't go wrong by staying at the Willard when in Washington, DC. Everything is within walking distance - great restaurants, the Metro, the Smithsonian, and many great shops.
Remember to look up when in the lobby for the seals of the states. The receptionist was very informative about the history of "lobbists".
If you enjoy a long, warm, soaking bath, the Willard has the best old tubs! Before you leave, take a peek into the Willard Room and recall the movies that featured this beautiful hotel.