Check out this Gallup Poll. Amongst Republican and Republican leaning independents, Sarah Palin is near the top of the Republican presidential field with the highest name recognition, tied for the highest "strongly favorable" rating, has a very respectable "favorable" rating, and given the unrelenting campaign by the political left (not to mention a complicit GOP establishment) to destroy her reputation, she has remarkably low unfavorable ratings as well. And she hasn't even declared yet!
There are certain things that are a bit misleading about the way Gallup represents the numbers. For instance, Herman Cain's positive intensity score might make some think he is a frontrunner, but if you factor in the rest of his numbers, such as name recognition, ballot support, etc, it becomes clear that he is nowhere near the head of the pack.