Christianity or atheism:
Christianity is perhaps the most vile ideal to poison the minds of men. It's uses, motives, and fictional stories are quite plainly immoral.
(http://aynrandlexicon.com/lexicon/religion.html)
(http://www.infidels.org/library/modern/richard_carrier/whynotchristian.html)
(http://www.goodreads.com/author/quotes/ 3956.Christopher_Hitchens)