Despite an entire week of debate prep, Joe Biden will still be Joe Biden. He will say a lot of very dumb things but he will say them all with the utmost confidence. and the media will do their best to declare him the winner no matter how badly he does. Biden will loudly blurt out some idiotic lie about Republicans, throwing his hands up in the air in exasperation... and then he'll put a big shit-eating grin on his face afterward. Most of the media will call this absurd lie the best line of the night and the moment that Biden won the debate. A few of the smarter lefty media folks won't even bother trying to defend Biden's awfulness, they'll just try to downplay the overall importance of the VP debate.
Paul Ryan will do great. He'll make a lot of really great points, and back up what he's saying with a lot of facts and figures. The media will do its best to portray Ryan's proficiency with math and familiarity with the budget as some sort of gaffe... they will try to say his reliance on numbers makes him seem cold and without empathy, or some such nonsense. They will also try to find some terrible problem with Ryan's body language, even if there is nothing to find.
Update: Doh! The VP debate wasn't the town hall debate, so you can scratch my first prediction... though I think that prediction will still hold true of the next debate between Obama and Romney.
Update: Lots of folks on the left want to think Biden won the debate. I think it's very telling that so many Democrats seem to think being a good debater means loudly interrupting and acting like a clown. He may have won the hearts of Democrats with his buffoonery, but I don't think he did himself any favors with independents. I was right about Biden throwing up his hands and blurting out a stupid lie about Republicans... he did that when he tried to put 100% of the blame for the "Great Recession" on the GOP, despite the fact that Democrats controlled both houses of Congress when it happened. I'm sure most Democrats loved hearing that sort of garbage, but I have yet to find one who's willing to call it the best line of the night.
Update: I was right about them trying to call Ryan cold. WaPo's Richard Cohen calls Ryan "cold", "plastic" and "too actuarial"... but Biden was somehow both "real" and a "hack with heart", whatever the hell that means.