I actually thought one of the most interesting moments was Obama bringing up the Terry Schiavo thing, since Schiavo's case wasn't even on the radar screen and hadn't been for quite some time. The fact that he brought it up out of the blue tells me one of three things:

1) He has a really fantastic pit crew who prepped him for the possibility this question might come up and worked with him in advance on a well-crafted answer.

2) He's getting better at thinking on his feet...right when the debates are done (for now).

3) He honestly felt bad about not standing up and saying something, but "going with the flow" as a freshman Senator, and thus it was the first thing that he thought of when the question was asked.

Any of the three is a good reflection on who he is and how far he's come.