A few quick points:
Most importantly, in the postseason, ALL THAT MATTERS IS HOW YOU PLAY ON THAT DAY. There is no "is." He "is" this or "is" that. Fewell sucks. Brees "is" elite. Anything can and will happen. There's a saying for athletes: you're only as good as your next game. I know it goes without saying but past performance does not necesarily indicate future success. Sure, Fewell's defense has had its share of struggles this season, but they've also gone through some pretty impressive stretches. That's the beauty of the game - the chess match, the execution - it all matters. There is no "is" in a consistent, non-fluid, quantifiable sense. Drew Brees has shown that he can play QB at an extremely high level, but that doesn't mean he will.
-The Saints defense can play like **** sometimes. Roman Harper's had a better year, but he's a guy a QB can really pick on for big plays. Same goes for Robinson and even Porter at signs. And their run defense isn't that strong either. And for as good as Drew Brees can be, the Rams tape from this year might be helpful to a team that can knock him down a bit. I'm thinking about the Lions or Giants. And he hasn't in a while, but he can throw picks.
-Matt Stafford has the ability to play at a level similar to that of Aaron Rodgers last postseason. This has become evident especially the last few weeks. With Kevin Smith giving them just a hint of a running game, that offense has the potential every week to put up 50. Detroit can also force turnovers and rush the passer a little bit. They also have nothing to lose and can play the 'no one believes in us' card as 10 point dogs against the big bad Saints in NOLA.
-As for the Giants, if they play the way they did last night, they WILL beat everyone and do 2007 all over again. We know they CAN, but will they? That's why we watch. Because of this, they're insanely dangerous. That lockerroom is a weird bunch but when they fly around and all play hard, they are as good as any team in the NFL.
So I say DET and NYG as most dangerous.
In the AFC, I'd be surprised with any other AFCCG than BAL-NE. I do expect DEN to shock PIT though.