Both Fred and Mitt play better to the economic conservatives, but are respectful of the evangelical conservatives. Huck pisses on the former, but is respected by the later. Sarah Palin is loved by both factions and is, therefore, the best choice.
Let's face it: The presidential contest has become a dumbed-down version of American Idol. Sarah outshines any of the guys out there with the possible exception of Bobby Jindal. She would, however, be wise to put one of the older guys on the ticket for the maturity and experience factor. Either Fred or Mitt would be good for roughly the same reasons-- both are decent speakers and debaters and both have been out of Washington long enough (or never been their in Mitt's case) as to be seen as a clean break from the past.
Since Huck is the topic of the thread, I just don't see what he has to offer. Economic conservatives despise him (and the feeling is mutual). Evangelical conservatives simply don't support him in large enough numbers to win any region outside the southern base. He adds a little in area of experience, but nothing in the area of maturity.