Gore's not really noted for his foreign-policy expertise, so I don't see him as Secretary of State. He'd be more of a Secretary of the Interior or Secretary of Energy type, though I doubt he'd accept either post.
I like the idea of McCain as Secretary of Defense. Although the temptation in a Democratic administration would be to freeze out the Republicans, as Bush froze out the Democrats, it would be wiser and would serve the country's interest better to include a couple of Republicans in the cabinet.
Norman Mineta, Secretary of Transportation 2001-2006 is a Democrat.
You're right, of course. I forgot about him.