Thinking about it, a Huckabee victory might not actually be the best result for those who want to stop McCain. Huckabee winning means his supporters will stick with him, but Huckabee losing means at least some will defect to Romney, who has a much better chance at derailing McCain in states such as Illinois and California than Huckabee does.
Huckabee supporters defecting to Romney. I really doubt it, but ok.
According to the exit poll, Huckabee picked up quite a few conservative Protestants, non-evangelicals, who might otherwise prefer Romney (certainly to McCain) or Thompson (but he's dropping out).