Woohoo! I agree with aWol on something!
W: The best day of my presidency was when I was sworn in as President and — because it gave me a chance to assume this high office and implement a strategy that would make the world more peaceful and more free and a country more compassionate. That's so far been the best day of my presidency. -- from the Diane Sawyer interview.

Definitely the best day of his presidency. He was only president for half the day. It's been all downhill ever since.