This is an idiotic idea for a list.
You can't rank these teams for many reasons. One reason, of course, is that they come from different eras...even before the cap and free agency era, I'd divide the history of the NFL into at least two eras.
More importantly, you can't rank them, because each SB Champion is like a diamond cut from a stone; diamonds can have flaws, but they are a product of the geologic forces that created them, just like SB Champions are always flawed but are products of how they got to the game.
The SB Champion won't always be the best team (though this year will possibly be an exception to that rule), but it is the team that survived the gauntlet of a full regular season and a set of playoff games to emerge at the top of the hill. A little bit of luck and a few calls that go your way are all part of who emerges on top. To demean any one of those teams, even the @#%#% Giants of 2007/08 because of the magic helmet catch is simply wrong.
I'd be more interested in a list of what someone knowledgeable thought was the best team each year over the past 50 years.
I say that along the lines of how they introduce the winner of The Open Championship in Britain; they introduce him as "The Champion Golfer of the Year," not as the "Best" Golfer of the year. I've always thought that distinction was important.
So, who was the "best" team in the League each year, whether they won the SB or not? There's no doubt in my mind that the Pats were the best team in 2007, just as there's also no doubt that they weren't the best team in 2001. But, I certainly don't know enough to express an opinion on teams from the '70's and '80's.