I watched the whole thing and wish I'd written some commments as I was glued to the set, eating my popcorn. I don't really have the time or energy for long comments, except to say that Obama was masterful in dealing with GOP dishonesty and obfuscatory cliches.
My bet is that the biggest impact, aside from fodder for political junkies who went in with their biases in place, was a mini-educational seminar for the media, who to date have shown little interest in unpacking policy and great love for the "horse race" talking points. They've acted largely like stenographers for any stupid accusation driven by partisan animus. But I heard a bit of common sense questioning of GOP talking points in the wake of Obama's Health Care 101 seminar. The best take-away I've read so far is, not surprisingly, Ezra Klein's. Here.
Update: More excellent insight via Andrew Sullivan, here.