to bring it back on topic:
Key Reason Palin Gave For Quitting May Be False | The Plum Line
apparently, the expressed reason is actually false. Not that I am surprised, but it seems like a lot of people are willing to throw her under the bus.
My guess right now as to why she quit has nothing to do with media, legal bills, or looming scandal: ever since she became a national figure she has dedicated more and more time to her national profile. Things like her declining stimulus money, for example, was a decision that seemed to pit her national ambitions and the staff dedicated to her national profile against the local staff and their priorities. I wouldn't be surprised if it just got to a point where her staff and supporters simply came up to her and said "either quit or we resign and hammer you publicly."