I think both teams have the ability to shut down the other and win convincingly. It will depend on whatever tone is set in the first quarter I think. If the Bears D comes out and gets to Manning early, I think it'll be over. If Rex comes out and throws a couple picks and a fumble or two like in that Green Bay game, forget about it.
In my mind though, Peyton Manning is still the modern-day Dan Marino: Stats better than anyone else in history, yet a perennial loser of the big game. This is his chance to prove people wrong.