I've been pointed to this article about Obama's reading. You probably have read it, but it's good to just take a look at the books that maketh a person:
Mr. Bush and many of his aides favored prescriptive books — Natan Sharansky’s “Case for Democracy,” which pressed the case for promoting democracy around the world, say, or Eliot A. Cohen’s “Supreme Command,” which argued that political strategy should drive military strategy. Mr. Obama, on the other hand, has tended to look to non-ideological histories and philosophical works that address complex problems without any easy solutions, like Reinhold Niebuhr’s writings, which emphasize the ambivalent nature of human beings and the dangers of willful innocence and infallibility.
What’s more, Mr. Obama’s love of fiction and poetry — Shakespeare’s plays, Herman Melville’s “Moby-Dick” and Marilynne Robinson‘s “Gilead” are mentioned on his Facebookpage, along with the Bible, Lincoln’s collected writings and Emerson’s “Self Reliance“ — has not only given him a heightened awareness of language. It has also imbued him with a tragic sense of history and a sense of the ambiguities of the human condition quite unlike the Manichean view of the world so often invoked by Mr. Bush.