McCain singlehandedly drove me to the Libertarian Party when I lived in Arizona.
I have since recovered from that little bit of insanity, but I won't vote for him NO MATTER WHAT.
If our choices are McCain for the Republican candidate and Hillary for the Dems, it MIGHT just be the first time in the last 100 years that a third party candidate has a 'snowball's chance'.
I'd vote for Lieberman as a Democrat (or Zell Miller should he decide to get back into politics) before I'd vote for McCain. There are a few other Democrats I'd vote for over McCain too.
Heck, Obama would probably be a safer President than McCain.