One thing that always proves to be true: what we think to be the case in September and October, about half of it turns out to be completely wrong by December. Cases in point: one year in the Bledsoe era, the Patriots started out 4-0. They finished the season 8-8. And one year during the Pennington era of the Jets, there was all kinds of hype over the 5-0 Jets taking on the 5-0 Patriots. "AFC Championship Preview!" the pundits all shouted. By January, that prediction looked pretty silly.
That being said, most teams won't be able to afford an 0-3 start, with the possible exception of the Colts.