As a full-time volunteer after college, I lived in a convent converted into the volunteer program’s offices. Across the street was an old church (not Catholic) that was being converted into condos. Despite the fact that we were living in a convent, my roommates and I argued whether we would want to buy a home in an old church—sacred or profane?
With churchs sadly closing, it seems that more are being converted to something else rather being torn down. Here’s a link to some unique rehabs  (thank to Neatorama).
If a church is no longer going to be a church, I would prefer it to be a book store, library, school, or something like that. It’s sad to see church’s becoming nightclubs and bars.
Ten it seems, isn't enough. This website lists a total of 40 unique churches in two parts . These are fascinating to see, and you may even find a church in driving distance of you. I've passed by St. Joseph Ukrainian Catholic Church in Chicago, IL many times. With its 13 gold domes, it's definitely a landmark.
Do you have an architecturally interesting or favorite church near you?
My brother just took me by a "green" synagogue  in Evanston last weekend--very neat building. Krista Tippet spoke about architecture on Speaking of Faith  a few weeks ago, including about a church that was reconstructed using parts of the old church.