The Packers were 15-1 in 2011 and got a bye.
The 9-7 Giants played on Wildcard Weekend and manhandled the Falcons.
In the divisional round, the Giants went to Lambeau (in January!) and beat the Packers convincingly, with a final score of 37-20.
Now that I think about the Giants, let's go back another four years to the 2007 season. The Boston Cheetahs ran roughshod over everyone (the Cheetahs offense scored 589 points - the next-best team scored 450 - and the Cheetahs defense allowed 274) and had an undefeated 16-game regular season. The Cheetahs then rumbled into the Super Bowl, and the out-of-nowhere, inferior-on-paper wildcard Giants allowed the surviving members of the '72 Dolphins to pop champagne on Super Bowl Sunday.
So hell yeah, "any given Sunday" and all that. The Seahawks are a reasonably good NFL team, and while the Gold Diggers are clearly the best team in the league right now, of course the Seahawks can compete.
The smart money's still on the Gold Diggers to win the division and make the Super Bowl, but as many have already said in this thread, the season is long. We can all remember examples of teams that looked like juggernauts in October and either crapped out before the season even ended, suffered a surprising early playoff exit, or (like the 2007 Cheatriots) got all the way to the Super Bowl and lost there.