The Colts don't have a solid defense, a solid running game, and have not proven that they can win in the playoffs. I don't expect them to be able to beat a Denver or San Diego in the playoffs. That being said, they'll get home field advantage and first week bye again (which is probably bad for them), and they're the best team in this regular season. They might even go undefeated. Dallas can beat them if they can get to Manning. That's how San Diego and Pittsburgh beat them last year. However, Dallas's defense is not Pittsburgh's of last year, so it's unlikely to happen.

And yeah, the Bengals can't play defense. And San Diego's defense has gotten a lot worse.