Sarah Palin has announced that she will run for president in 2012, "if there is no one else to do it." Now that the cat is out the bag, I don't think there's any chance she won't try to become the Republican candidate regardless of who else may put their name forward for the job, regardless of how much more better suited to be president they are.
Since Palin was plucked out of Alaskan obscurity by the McCain campaign she has undoubtedly done well for herself, with spots on Fox, a huge book deal, a documentary series, and so forth. However, while all this may have built up her popularity, she hasn't really shown herself any more suitable to high office than she did while running for VP, and that wasn't really all that good a showing, all things considered.
Across a wide swathe of issues, Palin has come across as lacking in the statesmanship field. Inciting hysteria by dreaming up death panels that didn't exist in the health care bill, provoking hostility to the builders of the Islamic cultural centre in New York, using inflammatory language and encouraging people to reload and take aim at Democrats, and much more paint a picture of someone who is catering to a narrow section of society, and does not particularly care for or respect the rest of it.
Besides for increasing her popularity and her bank balance (both essential nowadays for a wannabe president), she hasn't made much progress on other things necessary to being a good
president. She resigned as governor of Alaska halfway through her term, showing a lack of commitment to the responsibility the voters had entrusted her with, she still hasn't built up any experience with foreign affairs (support our troops is about the closest I've seen from her on foreign affairs, and that's more patriotic jingoism than thought out foreign policy), and policy positions that are a mix of opposing anything the democrats suggest and populist slogans with no thought as to the implications beyond the fact that it rates well now.
I'm not sure I want Palin to run, because although I think if she ran Obama would be a shoe in for reelection, I think it would be better for America if the voters had a choice between two people who would be a good president.