Washing outsider, conservative chops, young and female. Addresses a lot of the complaints about McCain. And not a long history in government to attack (Contrast with Biden). If you think about it, it's McCain vs Biden and Obama vs Palin. And Palin actually has governing experience, unlike the other three.
Given that Romney and Huckabee had their own baggage, it might just be the perfect pick.
Not much here yet, but:
http://www.ontheissues.org/Sarah_Palin.htm
