I don't think Rudy wants the job.
If I recall, the last time Ashcroft ran for an elected office he was beat by a dead guy. Ditching him would send a very positive message. Especially given that folks are already worried about the Supreme Court.
Powell kind of blew his wad when he presented all that irrefutable evidence to the UN. He took one for the team, but we need someone who can start a fresh relationship with the UN.
Rumsfeld ... I miss his briefings from during the war for their "Jack D. Ripper" appeal, but he doesn't seem to be that effective since the ground war ended. I think we need someone pretty forward thinking, our military will need to be more flexible in the future.
Rice ... we really need someone more pro-active. She does OK in her role, but her position is too important now to be left to someone who isn't more aggressive.