I heard a liberal Obama skeptic remark a couple of months ago that it would be a strange day in America when the correct answer to the question "who's the most electable" was "the black guy." I think that's right, and it's a reminder that though the cliché is to say that Democrats are torn between two very strong candidates, in some ways we're torn between two very weak ones. At the end of the day, I do think "the black guy" is the more electable of the two, because "Bill Clinton's less-charismatic wife" is an almost uniquely poor choice to try to expand the Democratic Party's appeal at a time when George W. Bush has brought the GOP into discredit. But in a primary election, where Clinton has formidable strength, it would have been extremely difficult for anyone other than "the black guy" to build a viable anti-Clinton coalition.
Given the extreme strong underlying pro-Democrat fundamentals, it's very hard for me to imagine how a "generic Democratic white dude" like Chris Dodd or John Edwards or, indeed, John Kerry would lose in this environment. Now of course given that white men are a pretty tiny slice of the Democratic coalition at this point, sooner or later the party is going to need to start nominating more women and non-white in competitive races or else they'll be shutting themselves off from too much of the available talent (see, e.g., Obama's formidable speech-giving skills) so it's probably just as well to spend a year with good fundamentals taking a chance and breaking down some barriers.