My worry about Bush is that he may end up giving tacit endorsement to McCain, and there is no way in hell I will vote for that nut, either in the primary or general. He'd inflict more damage to the party as President than any Democrat. The only thing positive thing I can say about Giuliani is on his active campaigning for our candidates (so at least he isn't a RINO in that regard, which Romney is after his screwing and stiffing of the MA GOP), although he's doing it to collect markers. But I still remember those days after the '94 election, sitting on a train leaving NYC staring at the commuters newspaper headlines musing whether Rudy was going to switch parties. Policy-wise, it's impossible to distinguish him on too many issues, and that would prove equally devastating to the party's fortunes for the short, and perhaps long, run.
The name of Dr. Coburn was brought up, but Coburn is probably too honest a person to be able to win. He's more than willing to tell the public what they DON'T want to hear, and the public, sadly, can't handle that.
The apparent heir to Bush is Rudy. Bush and Cheney will give indirect support to Rudy. Interestingly, GOP voters, who approve of Bush, like Rudy. Bloody RINOs, for some reason, like McCain, despite his pro-life record.
For me, I am undecided now. All the Rudy for President threads are pointless. He hasn't given any foreign and domestic polciies yet. I will sit and listen to the contenders.