I can't wait! It should be a great smath-mouth football game. A big difference for the Pats from last week will be the receivers- the Steelers receivers actually block (and well). Both teams are very physical and execute on both sides very well- like a few people mentioned, it will come down to who makes more mistakes. Or injuries. The Pats don't have quite the depth they once did- when the Steelers knocked Brady out last AFC Championship, the Pats brought in Bledsoe (their current backup is 8/19, 88 yards for his career!).
And just to mention, the Pats-Steelers game earlier this season doesn't mean much- the only way it would matter is if the Pats turned it over 2-3 times are were down 21 points in the first quarter again (and even with Dillon, at that point, it probably wouldn't matter). Also, Troy Brown, Randall Gay, and Asante Samuel are much better at CB now then they were the first time around (not the cream of the crop, but better nonetheless). It was that game that they first lost Law, and were also without Samuel and I think Wilson (FS) as well.
The Pats want revenge and the Steelers will be playing the "underdog at home" card- it should be great!