Alex Massie polls his readership, asking everyone to pick the most overrated and underrated U.S. Presidents, and I thought I'd offer my ballot in the form of a blog post. In the overrated camp, I'd place Woodrow Wilson and John F. Kennedy (both obvious choices, I think) and then throw in Harry Truman as well, whose reputation deserved to be rehabilitated from the nadir it reached during his second term, but whose current position as the bipartisan saint of American politics grossly overstates his virtues. In the latter camp, I'd place Eisenhower (whose reputation has risen, true, but not high enough for my taste), George H.W. Bush and Warren G. Harding - the latter for the reasons outlined by Ilya Somin here. (I certainly wouldn't haul Harding up into the near-greats or greats, but he deserves better than to be placed in the bottom five, just as his predecessor deserves far worse than his regular top-ten showings.)
All of my picks are twentieth-century figures, you'll note. If pressed on the pre-1900 chief executives, I suppose I would say that Chester Arthur and Grover Cleveland are slightly underrated (though only by virtue of being forgotten), and James Madison and Andrew Jackson slightly overrated. But with the exception of Lincoln and Washington, and perhaps famous debacles like James Buchanan and Andrew Johnson, I'm not sure how profitable it is to argue the overrated/underrated question where nineteenth-century Presidents are concerned, since the majority don't have sufficiently-defined reputations these days to really be counted either way.