We have a couple of times. Although I love Washington, there are areas where you don't want to be. Neighbours recommended two suburbs, Crystal City and Alexandria VA, both are in good areas and the hotels are much more affordable. One thing you have to watch for are parking fees at most of the hotels. They're steep. If you plan on seeing some of the sights, try to get a hotel on or near the Metro (subway). It's cheap, efficient and a safe way to travel.
Beth