Romney - and here's my 2008 Prediction map, which just so happens to be based on this situation.
how does Romney win WV and OH? I think Edwards's populism would go over well there, while Romney's northeasternness, mormonism, overly-managed campaign, and flip-flopping would be off-putting to a lot of people, especially those who've voted Republican for social issues the last few elections.
and do you really think he would win Michigain? Other than that his dad was governor there 40 years ago, I don't see anything there to make him more appealing than a generic republican.
this map I think is more likely: