Palin should have been the republican nominee. Not John McCain. She represents the future of the republican party a lot better than John McCain does. Had she, like Obama, been running for the past two years, and assuming that she is every bit as skilled in running a national campaign has Obama has proven himself to be, the country would likley have become comfortable with her experience and her positions. Based on what I've seen so far, I would vote for Palin for president.
Palin may still not be enough to sell the electorate on McCain, though I believe she will definitely help him nail down people who were unenthusiastic and might have just stayed home. The fact will remain that McCain is the top of the ticket and he is the one calling the shots. Not Palin. So at the end of the day its still a decision on McCain and on his promise that he is a different, better republican.