I saw part of it, and will see the rest of it later as I have videotaped it.
I think that in many ways, Ron Paul probably got the most out of the debate, for two reasons:
(1) He is a virtual unknown, so publicity automatically is a good thing for him. Everyone (at least everyone likely to vote in the primary) knows McCAin and Giuliani, and to a lesser extent Romney, so seeing their face and discovering that they exist is not a benefit for them. Paul on the other hand is going to get some recognition from the debate, which can only be a good thing for him.
(2) As the only anti-war Republican candidate, he can probably get most of the protest vote by GOP voters unsatisfied with the war. If someone who was perceived as anti-war (whether being so or not) but who was better known and considered more moderate - like Chuck Hagel - were running, Paul would probably be stuck at 1-2% with most antiwar GOPers voting for the "more moderate" candidate. But as it is, if you are GOP, wish to vote in the primary, and don't like the war, you have one option. Granted, this may only be 10-30% of the vote, but it's enough to keep him in the race and to get him some notoriety.
Tom Tancredo may have gotten a boost - I will have to listen more carefully to the immigration questions asked. But as at least some of the other candidates want to appear to be tough on immigration, he will have a harder time standing out, at least for now.
The best answers of the debate were when Tancredo pointed out that mandatory spending (entitlements) rather than discretionary spending was the elephant in the room, and when Paul pointed out that inflation was a tax. Both of them touched on things that otherwise would not have been mentioned.
That is all.