Perhaps the biggest difference is that people took a quick dislike to Obama (and Clinton), leaving Congressional Democrats to deal with an angry electorate at the mid-term elections. Public anger over Carter’s incompetence did not become universal until 1979, so the Democrats did OK in 1978. Of course, that meant that Carter had to face the first angry wave in 1980, rather than letting his fellow Democrats take the beating for him, like Clinton did and Obama is about to do.
Perhaps Obama, like Clinton, will learn from the spanking his party is about to get, but I’m not holding my breath.
I doubt whether he'll learn anything, but if Republicans win Congress he'll be able to bash and blame them for the next two years.
Democrats could pull through in November and we'll throw them all out together in 2012.