to the White House?
I might have to go with Al Gore but Ross Perot, Bob Dole, John McCain, Barry Goldwater, George McGovern, Stevenson and Thomas E Dewey are up there. Henry Clay but I'm not convinced any pre 20 century candidate would come to mind in most people since most people tend to be ignorant about subjects such as history and politics.
I think Henry Clay is more well known to the average person than Stevenson or Dewey, and for younger people Goldwater and McGovern arent that well known.
I'd go with Dukakis, Kerry and Gore from recent years. Burr and Clay from the past.