Jay Cost has a piece at Real Clear Politcs that takes the Choccola/Donnelly race in Indiana's 2nd district as the starting point for an argument that Democrats will either do much better or significantly worse than the current consensus of a 14-20 seat pick-up in the House.
His argment is that eight seats in blueish districts
are no longer seen as top tier pick up opportunities but that a similar number seats which are more Republican (like In-02 which voted 56% for Bush in 04) are in contrast now very competitive. I'm not sure if his conclusions about the eight blue districts are correct though I know that recent polls for at least the New Hampshire races are not encouraging for the Democratic challengers.
His conclusion is that either Republicans will "come home" in these Red districts and limit Republican losses or that the playing field will expand and that Dem pickups will be significantly greater than current predictions putting back into play the eight seats in blue districts that seemingly are now safer for Republican incumbents.