In his book, 'Audacity of Hope', Obama states he is a Christian. He was brought up with a Muslim father, whom had turned atheist. He states his Mother was a very spiritual person, but she didn't go to Church every Sunday.
He was baptised at the 'Trinity United Church of Christ' on the year 1988 and has been a member of the Church ever since. Obama became Christian by choice - not due to background beliefs.
I don't see how beliefs define how 'real' you are though, I believe a human should be judged on character, not the book they believe. All through his Presidential Career and the time leading up to it, it's always been 'First Black President', 'Is He A Muslim', skin and religion, I don't think America could've seen the real Obama even if they did want to, they were too busy sucking up all the media about irrelevant facts on him.
I hope he'll be remembered for his actions: the capture of Osama Bin Laden; the Withdrawal of Iraq and all the things he's done for America, not remembered only for his image.