I think the '09 Vikes will win 10-11 games with Sage Rosenfels at quarterback (which might give them third place in the NFC North). My worry with Rosenfels isn't his interception rate (though that's worthy of concern), but fear that his high competion percentage is a result of Gary Kubiak's offense (in 2006 David Carr completed 68.3%, in 2007 Matt Schaub completed 66.4%, and in 2008 Schaub completed 66.1%--Rosenfels' impressive completion percentage may be the proverbial product of the system). But from what I've seen, Rosenfels is a quarterback that can complete passes and run an offense (and at this point, that actually makes him appealing).
Rosenfels has to be the quarterback in 2009. With Tarvaris Jackson, you sacrifice any semblance of a two-minute offense, you are probably totally screwed if the defense and running game aren't winning a game for you, and you will wait knowing a game will come along when the majority of passes are bouncing all over the carpet, far from receivers' hands. Jackson doesn't complete a high percentage of his passes and rarely makes plays when the defense knows the team must pass. Rosenfels has his problems too, but I think he'll be able to do some things--things that the team needs--that Jackson just can't do.