President Obama has had his chance at picking a Cabinet and he's done a fine job so far. It's hard to pick from a crop of only real human beings so any fictitious characters are noted with an asterisk, but that doesn't mean they wouldn't be great.
Secretary of State Now maybe this one is too easy, but he does have a great sense of what's askew in America and could deliver bad news with a humorous delivery. Also his Bush impression kills me.
Attorney General You remember Clair? She was the Mom on The Cosby Show but she was also a whip smart lawyer. Do you think she would let any of this crazy "Is it torture? It's not torture" stuff slide? Would there be any doubt that she would get to the bottom of who leaked an American spies name to the press? When Theo and Walter decide to listen to a recording of "Macbeth" instead of reading the book, who would set them straight? Clair Huxtable that's who.
Secretary of Looking Fabulous Currently Mayor of SF but that head of hair is too good to waste on one city. If there were any younger Kennedy men around that wanted anything to do with politics then Gavin might have competition. This does require creating a Department of Looking Fabulous, but with the success of all these make-over shows - I think America could get behind it.
Chief of Staff Smart, known for keeping her co-workers productive and funny. Is there anything she can't do? I think she would also be motivated to make sure she never needs to resurrect the Palin impersonation.
Iron Man / Tony Stark *
Secretary of Defense. Technically I don't think the Iron Man suit would fit into a Hermann Miller chair in the briefing room. Of course this is America and we could probably get a government contractor to whip something up to the tune of $500K that would work for Tony/IronMan to use while be-suited. On second thought, let's just make him stand at meetings.