Assuming there isn't another financial crisis these hold more credibility.
Assuming you bought their September figures, and assumed that the financial crisis moved them. In any case, I think the margin is probably correct, but I am skeptical of Gallup polling it, since they get a number of outliers on a much more regular basis than SUSA, Rasmussen, or I guess after this year we can add PPP to the list.
I also think that the December of the year before an election is almost always the rock-bottom for the governing party. Look at Senator Kruger going down 68-32 in 1993, as well as the VA and NJ results, then see what happened in both states in 1994. Or 1995 and 1996. Or 1997, where it looked like the GOP might get to 60.
I think the reason for this is that people don't like Obama and don't like the Democrats. But next year they will also have the option of adding specific Republican candidates to that list. The GOP will probably have a decent year coming off 2006 and 2008, but given the present direction many of their campaigns seem headed, I expect them to be extremely vulnerable to a Democratic rally, especially in places like IL, CT, and NH.
Rasmussen has the GOP ahead by six on the Generic Congressional ballot.
http://www.rasmussenreports.com/public_content/politics/mood_of_america/generic_congressional_ballot