Reagan easily. Killed inflation, massively lowered taxes along with simplifying the tax code, and defeated the Soviet Union. His only 3 goals, and he accomplished them. Not only the best of the past fifty years but the best of the 20th century. And he did it with a Democrat Congress. Ofcourse, the large mandates he got from his landslide victories didnt hurt either. The fact that not even Barack Obama dares to talk about going back to a top tax rate of 70% shows just how much of a transformational president he was.
Bill Clinton? Hard to say. He was dealt a very good hand. Sometimes I think he deserves a lot of credit for not messing it up, because some presidents would have. But you know, he tried to mess it up in his first two years. However, in the end, luck, circumstances, the Republican Congress, and his own political and governing talent kept him from screwing it up. He deserves credit for hiring Dick Morris and taking his advice, and for working with the Republican Congress.
The fact that you guys think W Bush was such a horrible president is the reason we have the current embarassment in the White House. Certainly Bush was no where near an ideal president like Reagan. He was at worst mediocre and at best somewhat good. Certainly on the domestic front he was better than his father. People talk about what Barack Obama inherited, and it wasnt a good situation, but Bush was also dealt a bad hand by history. He had his faults and he made mistakes. While it took him too long to change course and correct those mistakes, atleast he eventually corrected them - both on the economy and on Iraq. Which is a lot more than you can say for the current president.