All Souls is a very cool Unitarian Universalist church in Northwest DC. It actually is across 16th Street from where we used to live in Adams Morgan "back in the day". I found the whole experience to be refreshingly inspiring. I heard mention of the application of a "reasoning approach" to religious faith within the first few minutes of the service. And All Souls is known for being a liberal institution with a focus on social justice. The congregation is made up of people from a wide variety of different faiths, including even agnostics and atheists.
We may attend once a month or so, possibly more, toward the goal of giving the kids a childhood experience of religion that is also appealing to us as parents; one that has a foundation of values that we can solidly get behind.
Oh yeah, and they also have a killer church organ