Leo Bottary, another one of H&K's numerous interesting bloggers, has been doing a series of posts on measurement that are well worth reading. They really give a good perspective on how measurement plays in the agency/client relationship.
On a separate note (yet another reason why the premise of Naked Conversations is dead on) I have to say that I've never liked Hill & Knowlton. They always seemed to me to be the worst of a bad litter -- PR firms that would do anything for anyone. I had issues with many of the clients they took on and found them bureaucratic and not entirely ethical. But thanks to their bloggers, and the numerous interesting things I've learned from reading them, I now find my opinion changing. Who knows, I might actually recommend them one day.