At least two people on my friends list, although it seems like more so I may be forgetting some, have recently used the term "fundie" to apply to those of the Christian faith. I realize it's only short for fundamentalist, but it's always felt derogatory and apparently that feeling was dead on.
From the wiki...
"The term is intentionally derogatory, and is used most commonly by those opposed to the Christian Right movement.
This is a derogatory term. Please do not apply it to people who share my faith. This applies to everyone, not just anyone who has used it in the past. Do not use negative terms for my religion, and I won't use negative terms for your religion/lack of religion.