I've got to believe that the Saints would present the biggest challenge.
My reasoning is this: come playoff time, you have to get extra weight to teams with veteran, star QBs that have won it before. There are only a handful of those team/QB combos in the league: NE, Indy, NO, Pitt, NYG.
Off the bat I think you can disqualify Indy and the NYG because I just don't think their teams as a whole are good enough this year (they may not even make the playoffs). And as much as it pains me to admit it, I have little hope that Pitt could beat NE--we just have never matched up well against your style of offense, and Brady's owned us over his career.
That leaves NO, which would appear to fit the other criterion necessary for beating NE--being able to throw and score with them.
I suppose there are other teams with a chance of derailing NE that *don't* have SB-winning QBs--Atlanta and Philly are both having very nice years with very good QB play. But somehow I just think the Brady/BB experience factor will win out in those games. I guess SD could conceivably score with you guys, but you'll be playing at home, not out on the West Coast.
In short it's kind of hard to imagine you guys not winning it all this year, but NO would give you the best shot...
I think the rest of us are hoping that you've somehow peaked too soon and DCs will find a chink in your offensive armor to exploit, or that a team whose style you're not as familiar with and/or you don't take as seriously will trip you up somehow in the playoffs (see: Cleveland). But that seems very unlikely; you seem hyper-focused this year, plus you have the '07 experience to remind you that nothing is truly accomplished until the end of the SB.
I kind of wonder if we'll look back in a few years and see NE's "smallball" 2010 offense (sort of a misnomer, since the results have been anything but "small") as a schematic leap forward, a key wrinkle developed to counter zone blitzing teams that other teams will copy. Although it's not the first short-passing offense ever developed (the WEst Coast O has been around forever), it does seem tailor-made to dismantling otherwise formidable blitz-heavy defensive schemes.
