It's worth bearing in mind that there's a third option. When Jim Fallows anticipated a different (though not entirely different) economic calamity in his big "Countdown to a Meltdown" essay for us several years ago, he framed the whole thing as a strategy memo to a soon-to-be-elected third party candidate, who was on the verge of triumphing after two consecutive failed post-Bush administrations, one Democratic and one Republican. This is obviously an unlikely scenario - but there's nothing written in stone that says the current two-party lock on the presidency has to endure unbroken forever, and a long L-shaped recession in which both parties look ineffectual is exactly the kind of time when unlikely scenarios start looking at least somewhat more likely. Ross Perot's 1992 candidacy, you'll recall, was premised on the idea that the GOP had failed and the Democrats couldn't be trusted; if Obama's presiding over an economic disaster in 2012, then a third-party run premised on the idea that the Democrats have failed and the Republicans can't be trusted might do rather well indeed.
Lyn Noziger had some thoughts about that, preserved here