On the merits, I think Santorum won and Paul arguably came in second. Politically I think Romney was the big winner.
Santorum just doesn’t have a lot of room to improve until/if Gingrich is out of the way. Romney desperately needed to keep Newt from surging and show some fire. He did that. It was his first solidly good debate performance in a long while. Meanwhile Newt clearly came in winging it without a plan to turn things around. I think when his attempt to turn the tables on Wolf fizzled it hurt him politically and drained him psychologically. He finished well, but sagged for a long time.
I would have bet before the debate that Newt was going to re-energize the race tonight and win the Florida primary. Now, I kind of doubt it.