Try the West End Cafe. I've read here from others that their experience hasn't been the best, but every meal I've had there was wonderful. It's in the One Washington Circle Hotel (I think that's the name) obviously on Washington Circle (which is where K, M, Pa. Ave., and NH Avenue intersect at about 23 St.) The rooftop restaurant at the KenCen is expensive; the cafe is just cafeteria food, but the Hors D'Oeverie (Sp?? what would my French teacher think) has little items that are really nice (I had a huge portion of CAesar salad with chicken for about 8 dollars that was enough for an entre even though they call it an hors d'oevre). The Hors D'Oeverie is in the same location as the restaurant so it's more posh than the cafe. You might like it.
Washington, DC