Top tier - Pats, Pack, Steelers and Cowboys.
Pats' record of sustained top-level success during the most recent free agent era of high-turnover instability isn't even close to being matched. Best coaching, and a history of players willing to sacrifice to become and remain part of the franchise speaks volumes about what's going on inside.
Pack have the league's best player at the league's most important position, and he's young enough to remain a stabilizing factor for the foreseeable future. To not only have a fanbase of their caliber, but to draw it from that market, in that climate, and have it prove to be that passionate for this long is just...wow.
Steelers have the best ownership in the game, and have an almost obscene track record of stability, identity, and relevance, and don't appear to be going anywhere soon. Also one of the two truly massive national and international fanbases, along with the Cowboys -- an artifact of being one of the two marquee franchises when the NFL first became culturally relevant across the globe.
Cowboys are tops in the league in terms of franchise value, visibility, popularity, and stadium, and now feature an ascendant team as well, with the strength being that offensive line that practically guarantees relevance for a while. The coaching staff appears to be stable, entrenched, and now successful. Only the ownership is a clown show, but there are enough superlatives here to warrant a spot atop any list.
Ravens, Giants, and Seahawks go in the next tier.
Giants, a few too many ups and downs in too big a market to stay front-page relevant year in and year out, but enough success often enough that they warrant a spot at the big boy table. They're what the Bears ought to be, if the Bears could get their heads out of their #####.
Ravens are doing everything right, and have IMO the game's consistently best GM. Another team with a well-established identity, too, and a QB who will steward them for a while yet. Only things that make them not quite marquee are that they're a bit more of a Johnny-come-lately, and have that lack of historical continuity that dooms them to second-tier cultural relevance. They're what the Raiders could have been.
Seahawks are ascendent, but have no real track record yet, so it's silly to put them on a pedestal with franchises that are historically great and also still relevant. Great, passionate fanbase despite all the guff I give them. And the only real demerit, IMO, is the well-hyped accoustic stadium. Bush league, IMO, but only a minor demerit. If they stay on top of the world for another decade like the Pats did, they'll elbow their way in.
KC, Indy just miss.