I agree with Jonah that a Hillary candidacy offers certain advantages to the GOP; I'm just not sure that this means the Democrats would be wrong to nominate her. As I've probably said before, Hillary may not be the best choice for the Democrats, but she's definitely the safest; I think nominating her more or less guarantees the party 48 percent of the vote, since she's sufficiently tested and savvy and all the rest of it to make a Dukakis or Dole-style wipeout almost completely unimaginable. And in a year when things will (probably) be going the Democrats' way anyway, there's a lot to be said for nominating a known quantity and assuming that, in spite of what Jonah rightly calls the "irreducible core" of anti-Hillary sentiment, the political landscape alone will ensure that her guaranteed 48 percent rises to 51-53 percent by November '08. Whereas Obama and to a lesser extent Edwards both have a higher ceiling, but also a much lower floor, since neither has been through the fire already the way Hillary has (indeed, Obama has never run against significant GOP opposition of any kind), and either one could flame out disastrously in the heat of a general-election campaign.
In the next Atlantic, Andrew has a long and (to my mind) largely persuasive piece making the case that Obama, out of the candidates running, is the most likely to be a truly transformational figure in American politics, carrying us past the polarization of the Baby Boom era into whatever's waiting on the other side. But the flip side of this is that Obama could also be a disaster as a general-election candidate in a way that Hillary almost certainly couldn't be - and for a Democratic Party that sees the next election as theirs to lose, the risk-reward calculus probably militates in her favor.
In a semi-related vein, I liked Ramesh's "one term for McCain" idea when he floated it months back, and I still like it now that he's re-issued it.
Photo by Flickr user sskennel used under a Creative Commons license.