Obama has been pretty equivocal in his professions of Christian belief, and I suspect he followed Lincoln's example in developing a certain canniness about public utterances in this area. (Perhaps in inviting Rick Warren to give the invocation he was compensating for a small credence?)
Be that as it may, I was struck by the soundness of his bibliographic classification: "In our household the Bible, the Koran, and the Bhagavad Gita sat on the shelf alongside books of Greek and Norse and African mythology."