Hard to say?
Steelers are hard to beat right now.
They beat the Broncos pretty easily, and they beat the basically "unbeatable" Colts, and they beat the Bengals.
Those were the 3 best teams in the AFC, and the Steelers beat them all.
Also, this could be the last year that Jerome Bettis will be playing football before he retires; so he has a lot to play for.
For the Seahawks: They beat the Panthers pretty easily. They beat the Redskins pretty easily.
Shawn Alexander is racking up rushing yards right now.
Matt Hasleback is a very good quaterback, and it is tough for a Defensive lineman to get to Hasleback right now, b/c of big tough guys on the Offensive line protecting him from sacks.
Seahawks have a pretty good defense as well.
Seahawks have never been to a SuperBowl before and actually, until this year, they have never won a Playoff game. So they have a lot to play for to win a SuperBowl that they have never been at.