My own little theory which may or my not have already been brought up (didn't see anything on it yet but I am sure I am not the only one who has thought of thie) - Cheney's little hospital visit was probably just a cold, but I don't think that will be the end to his health issues over the next couple of years. My guess is that Cheney will only last another year or two before he steps aside for "health reasons" so the NeoCons can hand pick their own candidate for the 2008 election. After Cheney steps down, the NeoCons will be able to confirm one of their own to the open VP seat, thus giving the future presidential candidate a springboard into the 2007 GOP primaries. Karl Rove and the rest of the posse don't like leaving things to chance. With the field wide open for GOP moderates like McCain or Pataki, the NeoCons will be pushing hard to make sure a fellow hawk who can also appeal to the newly empowered TheoCons will be sitting on top when the party ranks choose their next nominee.
Just my guess...
If anyone would like to comment on who they think would be Bush's sucessor, please do so.