The most compelling parallel I've read about between LotR and Christianity is a post I read that compared Frodo, not to Christ, as I expected, but to Job. In general, however, I think I'm a little skeptical about direct parallels ... I think there are themes that connect LotR with Christian ideas, but I don't think the characters and/or races are meant to be representative of specific figures. I'm open to being convinced, however. :)