Interesting graphics at Campaign Stops:
Between the Republican McCain and the Democrats Clinton and Obama, the former is closer to the center:
Nearly lost in the blizzard of recent poll reports were the findings of a Gallup survey that the current Republican frontrunner, John McCain, might well give each of the two Democratic frontrunners a run for their money.
When Gallup asked 1,598 likely voters whom they’d back if the presidential election were held today, respondents chose Senator McCain over Barack Obama by a 50 percent to 45 percent margin, and also preferred the Arizona senator to Hillary Clinton by a modest 50 percent to 47 percent margin. [Raising McCain. Campaign Stops. January 24 2008]
Personally, I am unsure about McCain. Though he does have an environmental credential (remember the McCain-Lieberman Climate Stewardship Act?), it is mixed at best while his grasp on economics is a turn off. He is also hawkish on security issues.