I wouldn't vote for McCain any quicker than I'd vote for Rudy. They would certainly be "lesser of two evils" votes.
McCain is too quick to cater to the media, and too quick to abandon conservative ideals. He's barely a Republican at all, and not really all that conservative either. Much like Tennessee's own Bill Frist, a guy I voted for, he was too willing to allow obstructionists to block judicial appointments, and too willing to roll over and go in with those obstructionists on other issues as well. His version of campaign reform wasn't, his version of immigration reform wasn't either.