Ronald Reagan was the greatest president America has ever had. Dealt Communism its deathblow, restored confidence in America, and brought us out of a recession so bad (20+% interest rates, double-digit inflation) that it may very well have otherwise slid into another depression.

As far as the worst, there are quite a few:

Andrew Jackson, whose "Tariff of Abominations" nearly started the Civil War 30 years early.

Abraham Lincoln, who invaded and annexed the Confederate States of America, engaged in brutal repression in his own nation, ordered Sherman's March to the Sea, and ushered in the most brutal rape of a nation that the United States--or most other nations, for that matter--have ever engaged in.

Franklin Delano Roosevelt, whose actions prolonged and worsened the Great Depression, and added to Stalin's power, causing problems that it would take decades to solve and cause untold repression before then.

Jimmy Carter, whose betrayal of the Shah allowed Khomeini and his goons to take over Iran, whose general wussiness with the Arab nations brought about an oil crises, and whose government policies gave us a thoroughly nasty recession.

But hands-down the worst--Bill Clinton.

Presided over the largest tax increase in American history, bombed a camel and a Sudanese aspirin factory on the day of Monica Lewinsky's testimony, started a bombing campaign in Iraq that just happened to begin the day his impeachment was scheduled, tried to blame the Oklahoma City Bombing on Rush Limbaugh, used the FBI to gather evidence on his political opponents, groped pretty nearly everything that wore a skirt and didn't sing bass, committed felonies to cover up his adolescent sexcapades, has at least one credible accusation of rape standing against him, nearly eviscerated our armed forces, allowed the build-up of Osama bin Laden's power and his many and varied terrorist actions against the US that culminated in 9-11--I could go on for pages without listing it all.