I don’t really believe Giuliani brings anything to the ticket with Romney. Romney’s already a northeast candidate, just about next door to Giuliani. Guiliani’s strength might be national security, but Romney isn’t that bad on that score, and Romney has the executive experience already.
Romney will probably have to pick a southern conservative acceptable to the evangelicals, to bring them enthusiastically to the table — but it won’t be Huckabee.
Of course Bush picked Cheney, and Bush 1 picked Quayle. So you never know.
How about Romney/Rice?