If you like the Kimpton shtick, you'll love Topaz. Great location on a quiet (as quiet as it gets, anyway) side street steps from Dupont Circle. A very good restaurant, the Tabard Inn, is next door.
We dropped in for a quick weekend getaway, and the service was perfect. Friendly, efficient and unobtrusive. The room was huge, and included daybed set off in a nook that would be perfect for a couple with a small child or two.