The 2007 Patriots were the most dominant team I've ever seen. Their offense was damn near unstoppable... so much so, that no matter what the odd makers put out as a spread, they out did it week after week.
I don't care that they lost the Super Bowl, that's just one game... to me, they're still the best team I, or anyone else, will ever see.
As for the Bills, I'm biased obviously, but I think one of their early 90's teams deserved recognition as one of the best teams ever.