I will admit I am hardly unbiased here. But I do think that Mitch Daniels has the best chance in the crowd presented. The big wild card currently is what Huckabee decides. If he comes on tonight and announces, the life get's interesting. If he comes on tonight and announces that he's not; then we are left with the same metrics, except that he is now free to endorse a candidate.
Romney is toast. Doubling down on the individual mandate in that speech was a disaster for him. The Obama White House putting out a statement thanking him for having a "smart" plan is going to be the equivalent of the Charlie Christ picture hugging the President. Romney's only hope is that several other candidates do very well, and he is able to capture a bare plurality. The vast majority of the Republican party oppose Obamacare and in particular the individual mandate. Given Romney's past history of "suddenly changing his mind" on critical issues (abortion, for example), he's not exactly going to be able to play off well that he Always Thought that Romneycare should be only limited to one state - particularly when he is on record saying things that sound very much the opposite.
Pawlenty would be a serious contender... if he could just get people and momentum behind him. A few excellent performances in widely-watched debates might get him some numbers, but whether they would be high enough to become anything approaching a consensus not-Romney candidate is rather questionable.
Huckabee hasn't been bringing donors online, hasn't got an organization set up, and is iffy on running. If he does run, he has an automatic base in our Fair Tax and Social Conservative constituencies; but this will be degraded by Herman Cain and Rick Santorum; neither of whom will be able to pose a real challenge to Huck, but both of whom will drain his support.
Palin is making money giving speeches, being on reality tv shows, and having fun playing Republican Kingmaker. She's not running.
Ron Paul has a small group of extremely devoted followers, a wider audience that has now moved closer to him.... and very little ability to turn the second into the first. He will play a positive role in the debate, keeping everyone focused on size-of-government and fiscal issues, but he doesn't have the ability to appeal to a wide enough section of the Republican Party to win.
Daniels biggest liability, like Pawlenty, is his lack of name recognition. However, he's spent the last couple of months lining up some impressive links that could go far to overcome that obstacle. Haley Barbour dropped out of the race AFTER building up what many observers thought was the best-organized multi-state campaign organization next to Romney's. Barbour and Daniels are good friends, and it is widely suspected that the first dropped out so the latter could run. Barbour's organization becomes Daniels organization. Everyone has been remarking how the usual big donors of the Republican Party are failing to fall in behind various candidates in the primary. The ones who commented have generally said that they are in a "wait and see" mode, and still wanting more people in the race. Now we have learned that Bush's old campaign staff have been quietly lining up all of his old big money lists to come out behind Daniels should he announce. A large-scale low-key advertisement campaign that synergises with Barbours organization to get out the word on Daniels accomplishments in office will go far to reducing his lack of name-recognition, and remain a powerful weapon as we head into primary season. Some think that Daniels weakness is that he isn't aggressive enough - this is Rush Limbaugh's position. No problem - Chris Christie is also doing everything but coming out and saying he would endorse a Daniels campaign - and there's no one more combative than Christie. The Lead Candidate becomes the picture of low-key competence and ability to turn a deficit into a surplus while Christie plays the part of smash-warrior. Walker, too, has been making signals that he would endorse Daniels, and bring to him the attention that Walker, as a Republican cause celebre, can.
Daniels biggest threat (should he choose to run, and I think he will) was Romney. Romney just shot himself in the face. His next biggest threat is Huckabee. We will see tonight.