I think Packers-Vikings increased as a rivalry this past year because of Brett Favre, but on the whole Bears-Packers is the biggest rivalry in the NFC North and it isn't even close. Honestly I think only Bears fans think that. I doubt you'd find many Packers fans who'd agree, and I'd say that goes back before Favre jumped ship. Yep. The Packers fans I knew at UW-Madison unanimously thought their main rival was the Vikings. Considering the Packers beat the Bears like a drum throughout a good chunk of the 90s and 00s, and also considering the Vikings were much more competitive against the Packers over that stretch, a lot of Packers fans don't see the Bears as being on nearly the same level as the Vikings.