I'm a member of my local Unitarian Universalist church (in El Paso, just down the street from Waco by SW standards), and it is very friendly to atheists and skeptics -- I would say 15% to 20% of the membership would identify as "agnostic" or more skeptical. However, it is also friendly to an array of other, much less evidence-based views. I'd say a UU church would definitely be worth a look, and would almost certainly be a better fit for a LW denizen than a "non-denominational Christian" one. But one might need to be tolerant of some rather silly beliefs. OTOH, I'm starting to take it as an opportunity to learn to "evangelize" (gently).