I'm gonna say Pittsburgh 24, Arizona 17.
The Cardinals are a bit of a question mark. The Steelers pass rush could wreak havoc, and Kurt Warner has been a turnover machine at times. At other times, however, he's like Dan Marino with his quick release, plus I don't think the Steelers can cover Larry Fitzgerald. On the other side of the ball, I think the Cards would do well not to blitz Roethlisberger. They seemed to play more for coverage against the Eagles (the announcers praised the Philly line, but Arizona was often rushing only three guys), and McNabb couldn't deal with it. Big Ben seems to be at his best when scrambling, so don't kill yourself by blitzing, I say, even though Ben is fumble prone. But maybe it all comes down to the running game after all.
I want Arizona to keep it close, but would be happier if the Steelers win. A Super Bowl team just doesn't play the way the Cardinals did versus the Patriots and the Jets in the first half. Oh, and I will be drinking and sharing homebrew.