My thought is, the heck with arguments about loyalty / the future. The Packers almost made the Super Bowl last season with Favre at the helm. They have a great shot of being in playoff contention again if they bring back Favre as their starter. As a Packers' fan, wouldn't you want the team to maximize its chances of winning now, rather than relying on a guy who is completely unproven?
I guess a lot comes down to whether the Packers think they can compete with New York, Dallas, and Minnesota this season. I don't think any of those teams are a juggernaut, and with Favre leading the team, they'd have the potential to at least make the Superbowl (I don't think they can win it.) Still, the team may have a different assessment.