Since I am not a politician or a businessman of any significant standing, it is virtually impossible for me to answer this question. Well maybe not. In one sense I would have to say both Presidents Franklin Rooselvelt and Trueman. primarily because without their leadership or the ways they have participated in "History" there is a good chance that the world could now be speaking German, and more than just Jews would have been turned into lamp shades and ashes prematurely. In that same sense, there has been no President that has been the "worst" to me personally, because like I alluded to, my standing in society does not grant me the "privilege" of being treated the best by one or the worst. If and when the day comes that I find myself being herded into a boxcar toward some sort of "detention center" without Just Cause then I will be able to answer your question with more specificity.
I'd say the best was FDR, for not only helping the US in the great depression by creating job plans but also helping us through WWII, which he wasn't able to see the end of. Worst, in my opinion Nixon, he was kind of and idiot and how he handled Vietnam and his presidency was appalling.
Worst Obama. He has done nothing but divide this country more than it already was. He has blamed Bush and republicans for everything. He takes no responsibility for his political decisions. He has added more debt than any president in history. He is on pace to have outspent and obtain more debt than all the previous presidents combined. Best presidents: Reagan, he cleaned up Carter's disaster. Lincoln, he fought for freedom of slaves and was honest.