Bush's Place in History.

[Dr_BuzzCzar]

Presidential Approval Ratings, Since 1950
Below are the highest and lowest approval ratings ever received by a president in a national opinion poll throughout his presidency.

President Highest - Lowest
Harry Truman - 87% - 23%
Dwight Eisenhower - 79% - 48%
John F. Kennedy 83% - 56%
Lyndon Johnson 79% - 35%
Richard Nixon 67% - 24%
Gerald Ford 71% - 37%
Jimmy Carter 75% - 28%
Ronald Reagan 68% - 35%
George H.W. Bush 89% - 29%
Bill Clinton 73% - 37%
George W. Bush 90% - 25% (ABC- 23%, Fox-25%, NBC-27%, Gallup-25%)

Sources: Can West News Service; CNN; "The Ups and Downs of Presidential Popularity," Ron Faucheux, Campaigns and Elections magazine. Rateit.com

I think this reflects the variances the public feels during a presidency and shows the need for time (decades at least) to evaluate and even then its going to be biased since there's no real metric to measure "best". I think I, or anyone else for that matter, could make as good a case for Lincoln being among the worst or conversely make just as good a case for him being among the best. Its all in how you evaluate those facts.