I'm only going to rank presidents who's term of office is up, and history can reasonably judge.
Worst (no real order to this.)
1. James Buchanon - Had the oppurtunity to stop the events that led to the Civil War, decided to let Lincoln deal with it instead
2. James Carter - Totally inept, clearly out of his depth at the job.
3. Woodrow Wilson - Campaigned against US involvement in Europe, but got strong armed by banking interests, he is the worst in a lot of ways.
4. Franklin Delano Roosevelt - Campaigned running against the Great Depression and only made the problem worse, his legacy is closing on on ruining this country.
5. Andrew Jackson - He did some good things, like getting rid of the Second Bank of the United States (We should follow suit with the Third) but constantly let his administration get caught up in scandals.
Best
1. George Washinton - He could have been the Emporer, but he chose not to, enough said but he was even better than that.
2. Abraham Lincoln - He preserved the Union at a terrible cost. Who knows, maybe if he had time his concilliatory policy to the South might have stopped southern resentment later on.
3. Ronald Reagan - He took a country that was in a morass and didn't believe in itself and made it strong again while spreading the cause of Freedom far and wide.
4. Calvin Coolidge - He aggressively reduced the size and budget of the federal government after WWI. The last president to do so. The country enjoyed an economic boom under him.
5. John Adams - He took the fledgeling US Navy and slapped the Barbary pirates around the Mediteranean, something not even Britain and France had managed to do.