I know I come at this topic from a position of bias, but I think Dr. Bruce Caldwell of Duke University makes some excellent points in this article (HT Division of Labour).
Over the years, I've said many of these things to people who ask why I'm interested in the History of Economic Thought, but I don't recall stringing all of these together and certainly not as eloquently as Dr. Caldwell has.
In a related item, here's a review in The New Statesmen of a new biography of Adam Smith that looks promising. Titled Adam Smith: An Enlightened Life, it takes a broad look at the man who became the father of modern economics.
Is it worthwhile to learn about the great economists? I think so. I've gained much insight from reading biographies and the master works of thinkers such as Smith, Keynes, and Schumpeter - certainly more than I would have gained by reading only biographies or only the master works.
Do you integrate the economists and their ideas into your class or do you "stick to the facts"? I look forward to your comments.