Hmm, I am not sure about the best, but for the worst I would have to said George W. Bush - mainly because I do not think he was trying to be the worst president, I think he was trying to be the last president, if you know what I mean.
I'd have to say that Franklin Roosevelt and Ronald Reagan were 2 of our greatest presidents. I would have to say George W. Bush for the worst. Just because he doesn't try to be the president. He goes along with what his advisers say and he doesn't really contribute to the decisions in our country.
In my opinion Lincoln is the best because without him, slavery might still be around, and we would be 2 different countries, and be weaker countries.
The worst would be George W. Bush because of the war and the way he has run our country.