I've been to the Rothko Chapel in Houston but it is hardly my church of choice.
Did you get a chance to really study the Rothko Chapel? I arrived one day at 4:50 (the earliest I could get there) and 5 of the minutes before closing was spent buying slides. I really wished I'd had more than 5 minutes to really study and think about it. (I was just passing through.) It looks so much bleaker than his other works; I like the rectangular ("grave") images in his other works. They move for me: spatially, visually, spiritually. But the Rothko Chapel just seems dead. Well.....he killed himself before it opened. Maybe there's a connection...
Gee, seems like I've seen that Stuckist quote a lot lately. :)