Washington was the best President. He was a war hero so popular that he won the electoral college vote unanimously, and unlike every other veteran president, he kicked ass as a politician. He was our only independent president, and the shunning of his anti-political party philosophy has severely hurt the country ever since. Washington set the example for presidents; all others are judged by his performance. Certainly his terms were not perfect and have indeed been glossed over since then, but the man very clearly kicked ass.
Herbert Hoover is a pretty easy choice for worst president, but FDR wins the award for president with the most historically candy-coated reputation. His social programs didn't pull America out of the Great Depression, WWII did. He was a fine war-time president, but the "ABC" social programs he instituted have unfortunately been propogated over generations when they were only meant to be short-term solutions. For instance, the government-subsidized Tennessee Valley Authority (TVA) electric company in Alabama has effectively shut out private competition for decades, because it still receives Depression-era federal funding which allows it to set prices that other providers can't approach. All Americans are paying extra so that the citizens of Huntsville and other cities in the area can have cheaper electricity; I'm sure Californians would be happy to learn of that.
FDR is also responsible for moving our government much, much closer to an authoritarian system. The presidency became many times more powerful during his terms, as a result of his personal egomania (four terms in office!) and a pussy legislature that was so afraid of the Depression that they gave him whatever he asked for. One hundred-fifty years after Washington refused to be called "Your Highness" by the Continental Congress, FDR transformed the office into a position of power few kings in history could rival.