Then what is the ultimate aim? Surely you're not postulating that the ultimate aim of *most* people is to lead meaningful, productive lives of personal integrity beyond mere happiness?
Since Haloscan appears to trash old comments after a while, I'll reply here, because I want to record this indefinitely.
As I state in that comments thread, I don't believe that the things people value besides happiness are necessarily noble. They can equally well be craven, or egotistical, or founded on irrational hate. But the point is that people do have attachments to values that would not be called "happiness" by any usual definition of the term "happiness". People want happiness, but they find happiness valuable only insofar as it is obtained in a manner consistent with their ultimate values.
For example, all human beings could become "happy" by giving themselves a lobotomy. Most humans would not, however, choose to become happy in this fashion, because the thought of being a happy drooling idiot is somehow unattractive --- even though that drooling idiot would have no conception of the inadequacy of his/her happiness. This observation doesn't paint humanity as particularly noble, or possessed of very much integrity, but it does illustrate that the experience of happiness alone is not the ultimate aim.
So what is the ultimate aim? Perhaps it is to be happy for the right reason. But in this case we can simply drop the happiness as an end-in-itself, and understand happiness as a motivating force that drives us to bring about those right reasons. In Aristotle's classic categorization, happiness is therefore an instrumental good, not an intrinsic good.
Interestingly, this conclusion has some vague, poetic resemblance to recent findings in neuroscience (via Brain Waves):
George Loewenstein then explains: ''Happiness is a signal that our brains use to motivate us to do certain things. And in the same way that our eye adapts to different levels of illumination, we're designed to kind of go back to the happiness set point. Our brains are not trying to be happy. Our brains are trying to regulate us.''