I have to agree with Kay on the entirety of her post.  Without Gore, climate change is still a fringe movement instead of being up there with the economy, war on terror, Iraq, and health care as the most pressing issues on voters' minds.  And he has done all this without the bully pulpit and policy tools that world leaders have. 

I think General Petraeus is an interesting pick as well, though perhaps for next year.  He has turned around the debate in Iraq from when are we going to withdraw to how large of a force can we reasonably maintain there. As Tom Ricks said at a recent Campus Progress event, he is the first general in charge of the Iraq war that has actually understood the nature of the conflict and created real military progress (though no political progress).  Petraeus has certainly had an enormous (mostly positive) impact on arguably the greatest foreign policy blunder in U.S. history. So much so, that Iraq is no longer driving the national political debate.