I think James Fallows summed things up very well:
"Ifill, moderator: Terrible.
Palin: "Beat expectations."
Biden: No mistakes.
The race: No fundamental change. Which is better news for Obama than McCain."
I think he's pretty much right about everything except for the last point. I think by beating expectations, Palin at least stopped the bleeding somewhat for the McCain campaign. They can probably keep her away from interviews for the next month and get away with it now that she seemed semi-competent at the debate. But, all in all, Fallows is right in the sense that it's hard to see how Palin's performance will actually make much of a dent in Obama's lead.