NBC calls it for Hillary.
I'll borrow AS's premature post title and say, "It's on now".
Both candidates will get a thorough vetting. I think this is good for the process, as long as it doesn't go bitterly negative. We'll get to see if both candidates have a second and third act - that's really important, too. We'll see their capacity to take feedback, learn, and even to actively manage a staff or stick with the same people too long (a Bush Achilles heel).
This is where I bow out, except to keep 'em honest, mostly.
On a personal note, although my head is with Hillary, my heart is with Obama. If he can bring young people into the party in great numbers, they have the attitudes I want, even if they often seem like a bunch of gamers to me (I like gamers - Goolsbee, even, seems like a gamer to me, sometimes, on TV).
I'm old enough to be a one issue voter, although I won't admit it publicly. I don't think Obama's heart is better than Hillary on the issues of ridding the nation of its prejudices, especially against gays and lesbians; but he'd have more leverage to make it happen within the Democratic party, even, if he can broaden the base in the way that Hillary is not going to do, so far as we can see right now...