In honor of Presidents Day, CSPAN has released the results of a survey of historians to rank the presidents. Lincoln, Washington, and FDR are the top 3 in that order, followed by Teddy Roosevelt and Jefferson. The worst presidents (in order from worst to best) were Buchannan, Andrew Johnson, Pierce, William Henry Harrison, and Harding. George W. Bush ranks 36th out of 42 (Obama isn't included for obvious reasons, Grover Cleveland is only included once).
News story from WTOP Radio: http://www.wtop.com/?nid=116&sid=1602279 (http://www.wtop.com/?nid=116&sid=1602279)
Results of the survey from CSPAN: http://cspan.org/PresidentialSurvey/presidential-leadership-survey.aspx