ANOTHER INSTA-POLL:

Will Sarah Palin help McCain’s campaign?
Yes, naming her was a game-changer.
Yes, somewhat.
A short-term boost, at most.
No impact.
No, it will hurt his campaign somewhat.
No, it was a disastrous error.
  
pollcode.com free polls

UPDATE: From the comments:

As an aside, Palin’s story is about as different from Obama’s as one could imagine. Yet both are quintessentially American. As the man said, “What a country!”

Indeed.