This year's Superbowl feels like it's the most talked about one in a long time. It could be because of the big players (Manning) and big personalities (Sherman). It could be because we've already been talking about both teams throughout the season as they are both 1 seeds who have led wire to wire (last 1 seeds to play each other: Colts vs Saints '09). It could be because it's a matchup of the top ranked offense vs the top ranked defense (last time this happened was Bills vs Giants '91). Whatever the reason, there's already plenty out there about this match up, so I'm not going to go into a long and thorough preview.
Seattle to win
One of the key plays that the Broncos run is a corner timing route where Manning lobs the ball to the outside like an end zone fade. The ball gets there about the same time that the receiver (usually Demaryius Thomas) turns his head. It's been a very successful play for them, usually netting about 15+ yards and moving the chains. From what I've seen, the defensive player almost never turns his head around in time. However, with Seattle's ball-hawking corners, I don't think it'll work. If Seattle can stop this play, many of Denver's drives will be in jeopardy.
Seattle relies on those corners a lot to hold their own in 1-on-1 coverage. It's allowed them to keep an extra defender in run coverage or to spy on running QBs like Kapernick and Newton. To slow Denver's passing game, I wouldn't be surprised if Carroll took that extra defender and used him to doubleteam Welker out of the slot. If Seattle can indeed contain Welker and neutralize that corner route, Denver won't be able to sustain the drives they need to score enough points to win. My guess is this game will play out like Denver's loss at San Diego earlier in the season.