I can remember a number of specific incidences throughout the series where christianity is dismissed as irrelevant and lacking any power:

-Can't remember the season or episode, but the standard argument about paganism/ wicca being older than Christianity and thus more powerful is employed.

-Reference is made to the unusually large number of churches in Sunnydale, and spoken of as though when so many bad things happen in a town people flock superstitiously to a source of comfort.

-The episode in season four where Buffy and Faith swap bodies, it turns out that Buffy's boyfriend, who has always seemed a bit straightlaced and dullish, goes to church.

-There is an episode in season four where a frat house exhibits dangerous poltergeists. The explanation (and fair enought too) given is that the former matron of the house was a bit of a wowser who made the former residents feel guilty about their sexuality, the repression of which was exhibited in such poltergeists.

This portrayal of religion is typical of the Buffy series. I don't really care about upholding christian values, but I think values of loyalty and friendship (scooby values) transcends religion.

And yes, the main reason we all watched it was it was really-super-cool. No, we're not nerds at all, are we...