Best answer: toss-up between Kasich on health care and Christie on entitlement reform. Kasich just might be my new favourite among the Republicans. Even if governors in debates are seriously a pain in the ass with the endless litanies of numbers.
Trump: absolutely never. Even if Republican voters don't reject him for all the right reasons, and I fully believe they will, they'll reject him for the wrong reasons - his past support for a single-payer health care system and his pro-choice stances.
Economic ideas that make enough sense to convince a seventh-grader are apparently not a requirement anymore to run for president - hearing Huckabee and Carson talk, you'd almost think there is a Biblical prohibition somewhere against touching economic textbooks. Gotta love Trump's reasoning, too; I suggest "Let's Chapter Eleven the USA" as a new campaign slogan.
Generally speaking, I would consider voting for a surprisingly high number of these guys (at least four and possibly even up to six ), on the condition that they promise to put someone sane like Condi Rice or Dick Lugar at State and just let them handle things.