Would be Lieberman except he's not really a Democrat. John Edwards isn't really relevant in politics anymore so it'd be silly to include him. Kucinich might qualify but he's on his way out. Dodd is kind of noteworthy for how awful he's been since leaving office (heading the MPAA and massively pushing for SOPA), but I'm not sure if that'd qualify as a "politician". And most right wing Blue Dogs are now gone.
I might have to go with someone blatantly corrupt like Rangel. Sheila Jackson-Lee deserves a mention because of this
So basically the entire Dem field in 2008?