I'd say the two favorites going in are New England and Pittsburgh, with San Diego and Indy as the underdogs. Indy will basically have to score 40+ a game from here on out to stay in the playoffs... San Diego is good, and they certainly suprised everybody this year, and while they are a complete team, I don't think they can compete with the Pats or the Steelers.
The Steelers, I think, will be able to slow down the Indy offense just enough to make it an even game, while their own offense drives it up Indy's gut.
Eh... I see it hard for anybody to beat the Steelers at the moment. They do everything. Another team can even make their offense one-dimensional and they will still rock. They eat up clock time with an unstoppable running game, score whenever they feel like it and send opposing offenses packing. I mean, their second string defense just humiliated the Bills who were playing with their all to get into the playoffs.