I think Giok is right that Dean should stay far from Clinton personally, but can cite Clinton's record in areas where he agrees with Clinton, like "I would have a more Clinton-like approach to fair levels of taxation and balanced budgets."

Clinton's stigma is not really because of what he did, it is because of the media reaction to it. Many previous American presidents have had extramarital sex in the White House and elsewhere, and the idea that you couldn't be a good president while sleeping around is a fairly new idea. But the media decided at the end of Clinton's term that they had to turn on him in order to ingratiate themselves to the new administration, and you got all kinds of hatchet jobs reported in the press from "he took gifts of furniture and art objects that should have stayed in the White House" to "Clinton's staff removed all the W keys from computers in the White House just spite Bush (whose nickname is W.)" Clinton was essentially chewed up and spit out by the media, and the actual nature of his indiscretions had little to do with it.

The result is that a personal connection with Clinton would probably hurt Dean. But most Americans recognize that Clinton was much more successful than Bush in some key areas, and thus a connection on the level of policy in those areas might well help him. Having Clinton speak at campaign events, as long as the speeches are policy-focused, might even work. But having Clinton on the ballot would distract from substance and bring the discourse to a lower level.   

At this moment, I think Hillary would kill his chances of success too. She needs to build a bigger base of support and more experience in the Senate first. She is otherwise vulnerable on three counts: she failed at health care when Bill was President (for whatever reason, her fault or not), she has very little experience in policymaking, and the right hates her with a rabid, irrational passion.

I think Dean's best chance may be the tried and true method: selecting another of the Dem candidates, if they don't kill each other in the primary campaigns. How does Vice President Moseley-Braun sound?