Well, since I taught American history, I can't choose one, but I can answer a couple of questions:
Andrew Johnson was impeached but not dismissed. A fellow named Edmund Ross was the pivotal vote in the Senate. (Kennedy's Profiles in Courage)
Booman (I think) is thinking of Thomas Dewey, governor of New York who went to bed thinking that he was president. Give em hell, Harry won.
Any other questions? Oh, yes. Polk was a dark horse.
And a little showboatin' here. The first seven presidents were dubbed the Virginia Dynasty

and Dubya has been dubbed...er..ah...something or the other.