I've actually been working on converting a Hillary supporter where I work to McCain. She's in her late 40s (I think) and a "true believer" of Hillary's--but she told me that she absolutely will not vote for Obama. I've suggested McCain, and she's fairly receptive to voting for him.
When I asked her why she won't vote for Obama, she said a couple of different reasons--the whole sexism angle, and his inexperience, and his naive approach to foreign policy.