Oystein Elgaroy was one of the top xian apologists in the world and seen as one of the few scientists to believe in a sky daddy. I say was because he was so bowled over by Chrisopher Hitchens arguments and intellect that he is now an atheist. You can read about it here
Ofcourse this is not the first time that the xian apologetic community has lost one of their big guns. People like John Loftus were right at the top of xian apologetics before realising that they kept loosing debates and decided to convert. bart erhman was studying to become one of the top xian scholars in the world but studying made him loose his faith.
i would recommend this site which lists people who studied their faith and realised it was wrong