McCain, Romney or Guiliani would all have to select a running mate that can gather and motivate the conservative groups. All 3 of these guys can attract fiscal conservatives and many moderates, however they lose the NRA, religious and Pro-Life votes...which are core numbers for the GOP.
The one thing about Rudi is he'd foce the Dem (whoever it is) to actually campaign in CA and NY seriously...which would make a number of other states harder for the Dems to win.
Personally as long as Hillary or McCain don't win, I guess I'll look at the next President as better than the worse case scenario.