As new forms of congregations arise, new musical forms are developing. Walls are coming down—secular vs. sacred, intellect vs. emotion, contemporary vs. traditional.
In the evangelical subculture of my youth, there were three categories of pop music. There was secular music, the avoidance of which was, as with alcohol, a nonessential of the faith. (My parents’ approach was more tight regulation than outright ban.) There was Christian music, the Nashville-industry pop records that we heard on Christian radio during our school carpool and then saved our allowances up to buy. And then there was worship music, which we sang at church.
I will be the first to argue that good church music can be old or new, classical or pop or folk or whatever, content dense or repetitive, celebratory or somber. And as I've pointed out before, the best critiques of praise-band music usually come from within that world, not from outside haters. Anyway, this "How to write a worship song (in five minutes or less)" tutorial from Blimey Cow is a heap of fun.