My thoughts: Fred Thompson won hands down, followed by McCain. Here's a choice clip of Fred taking on Huckabee, who "caught flak" primarily from Fred:
Strangely, Ron Paul was the only one who took on McCain, and Paul would have gone away performing better than usual, but he slipped up big time:
A pretty good debate, and I've watched them all. The only mud flinging was from Fred to Huckabee, and a little from all to Paul, but Paul, other than his slip up, fought back fairly well.
For those who missed the debate you can catch it all here. Or here.