...which is a measure of expertise.

The meta-narrative of 2008 is already a search for strong, fresh, post-Bush leadership. Your favored candidate, Hillary, is not leading on anything, and she's the candidate of the establishment, which in the strengthening anti-DC, anti-establishment mood of the electorate, both primary and general, will be a hindrance.

Then, there's the fact that white Southerners generally do well in Presidential contests, while Northeastern Senators do not. That argument will carry increasing weight as we get closer to the actual elections. Polls at this moment in time really don't mean that much, unless they're of high-information voters (that is, not Wallner), and Edwards scores at the top of these; cf. DKos and MyDD polls. Plus, he's got the unions and trial lawyers sewn up, which means boots on the ground and money in the bank.

As to Obama, what I'd be really excited to see would be an Edwards/Obama ticket. I like the guy, I really truly do, but I think he has some major weaknesses as a candidate. He'd make a great President, no doubt, and I think he will someday; I don't see it happening yet, though.