While I'm hardly an expert on churches, or religious demoninations, there is no reason to believe that Smallville would only have one church.
According to the TV show, Smallville has a population of 45,000, which is patently absurd, but that's what writers who come from cities with populations in the milliions think is a small town.
But, even given a population more logical it would depend on the make-up of the town's people, and the surrounding farms. Maple Lake is a small town near where my folks used to have their cabin, and later lived. It has less than 2000 people in it. They have both a large Catholic church (they majority of the town claiming to be catholic), and a small non-denominational protestant church.
Granted, this is coming from someone observing from the 'outside', but it seems that Protestant groups are more flexible in where they might go to worship, whether it be Methodist, Luthern, or whatever. But Catholics who adhere to their particular precepts seem less likely to 'get their religion' from a non catholic source.
So, what I'm trying to say is... Unless the religious make up of your Smallville is overwhelmingly of one faith, you're likely to have more than one place of worship, however small it might be.
Tank (who nevers argues matters of faith with others because they only raise questions that can never be answered in life, but will be answered for everyone after they die)
