Definitely lean to the over. As you said, both Ds are banged up and/or not very good and Favre has a history of lighting up the Bears. However, the only thing that scares me is that the Bears O can be downright awful at times. They're Jekyll and Hyde almost from one series to the next. Also, if the Bears do get the running game going (which has only really happened once this year, against NO), they will look to drain the clock. Somehow, though, no matter how inept the Bears look on O, they still seem to manage to put up 20-some points a game.
Not sure if I'll bet it or not, but do think you're on the right side.