Vodkapundit uses the "Nice Guy" test in an early handicapping of the '08 race, and in the comments, there's a turn towards McCain as winning the "Nice Guy" race.
McCain as the nice guy? This guy doesn't look all that nice. Nor this guy. And this McCain and this McCain somehow remind me of this guy.
His premise might be right, and of course it'll all be in comparison to whatever villian the D's will nominate, but I have a hard time believing that McCain will ever be able to pull off the "Nice Guy".