This is a tough one. The most popular Presidents, in chronological order, were: Washington, Jefferson, Monroe (Era of Good Feelings, anyone?), Jackson, McKinley, TR, Harding, Coolidge, FDR, Eisenhower, Kennedy, Reagan, and Clinton.
I'm not sure Coolidge's popularity was ever that high. Lincoln, Grant or William Harrison were quite popular in their day as well. The Bushes had approval ratings in the 90%s at some point. Most historians that I've read consider Lincoln the greatest president, but of course he was tremendously unpopular in the south.
Also Nixon and Johnson were elected and re-elected with over 60% of the popular vote, but fell from a high pedastal.
It's a tough question.