I've been thinking Juliani
but I could vote for a McCain/Liberman ticket.
Who ever it is it will need to be someone presidential (at least as much so as the current cast of potential potus nominees). Guys like Huckleberry and no names need not apply. With a younger more vigorus candidate, Bob Riley, the current AL govenor has been outstanding would be a natural but he will not fill the bill for McCain.
The age issue could be huge with McCain. He doesn't look very healthy, regardless of his true physical condition and isn't he older than Reagan was when he ran?