I see a lot of down sides to many of these people named. In stark realpolitik terms I don't think a woman on his ticket flies. A black and a woman is too much change for to many people. Sam Nunn is a good pick, but he's been out of the limelight for a long time, he is probably rusty on the campaign trail, and he takes the "age" issue off the table.
He'd be a great foreign policy advisor, or Sec of Defense, not a VP. I think Hegel is qualified, but the move is too cute by half. Hegel is a lifelong Repulican, and while maybe he delivers Nebraska, maybe he doesn't. People could see it as disloyalty, and he could be viewed by republicans and independents as a turncoat, thesame was dems and many independendants look at Joe Lieberman.

Ohio Gov could carry Ohio and maybe help in Pa and Mich which could turn the election, his weakness is no foreign policy chops. McCain, who is no foreign policy whiz, is overrated in this department, but he has the "security" vote locked up and can engage in fear/warmongering, as he has already begun to do. Takes me back to Jim Webb. Former Navy Secretary under Reagan, strong military creds, strong security creds, can get down and dirty with the common folk, and could deliver Virginia, North Carolina and help tip Pa and Ohio. He would be weak with women voters, and apparently has said or written some sexist things that they would throw back at him.

As for McCain, I don't believe for a minute that he is taking any one other than Romney seriously among the three names he has floated. The guy from Louisiana has less experience than
Obama, and Charlie Crist of Fla is also inexperienced, and McCain will robably carry Florida anyway, uness a hurricane hits and the shell game the Republicans are playing here with insurance is exposed.