I know it was mentioned earlier, but he deserves his own thread.
He loved American history and excelled at telling it's stories. He shed light on men that history had brushed aside. He narrated the American story, from the revolution, to our civil war, to the 20th century.
He also astutely identified the widening American historical illiteracy epidemic, something I think that will eventually lead to the downfall of the America he loved.
We need more David McCullough's, but they don't make him anymore.