A few thoughts:
1. The debate started off very civilly, but then there was enough fight - I enjoyed it!
2. I think the debate was at least a draw, if not a victory for Senator Obama. Even a draw helps Senator Obama - there was a good reason the Clinton campaign was clamoring for a debate a week. On CNN, Donna Brazile said, "[Obama] was Presidential... he had the poetry, but also the prose. He was good!"
3. Senator Obama threw a few good punches, as did Senator Clinton - but I think Senator Obama got the better zingers, like "this is silly season in politics" (video) when asked about the plagiarism charge.
4. More importantly, Senator Obama defended himself well against the charge that he is all talk and no action. He specifically stated many of his legislative accomplishments, and got one of the best lines of the night - that the Clinton campaign is trying to paint Obama supporters as "delusional."
5. Senator Clinton repeatedly went back to health care, but Senator Obama got back saying mandates on adults haven't worked in Massachusetts (which has mandatory health insurance) - people can't afford insurance, so they end up paying fines without getting any benefits! He also pointed out why Senator Clinton's 1993 efforts to get universal health care failed - because she didn't even include the views of other Democrats, let alone Republicans and stakeholders.
6. I can't really tell how effective - for lack of a better word - the CNN "people meter" is. The few snatches I did see, Senator Clinton was getting consistently good scores (i.e. a more positive response), which speaks to her debating skills. However, the one clear negative period for her came when Senator Clinton tried to repeat the plagiarism charge against Senator Obama. That line isn't working, girl!
7. CNN commentators are saying that Senator Clinton's last answer to end the debate got a standing ovation. Roland Martin, also of CNN, had a different take - he said people related to Senator Clinton's hint at her trials and tribulations in the 90s, but they also stood up because she gave a generic unifying answer to end - "we Democrats will win November" or some such bromide - and it was the end of the debate. So the standing ovation could well have been for the debate overall.