This T-Nation http://www.tmuscle.com/free_online_article/sports_body_training_performance/the_overhead_press_bodybuildings_forgotten_muscle_builder contains a good explanation of this exercise and why it's been largely forgotten in bodybuilding circles. By "overhead" press, the article is referring primarily to what is often known as the "military" press, and its variations.
The distinguishing factor is the standing nature of this press. The seated overhead press is, after all, still quite common in gyms. But how many lifters are performing the standing overhead press? Not many; in fact, in my gym, I've observed very few performing the move.
Fact is, the overhead press is a fine barometer of overall strength as well as key in developing the deltoids. And unlike that current barometer of strength in the mind of most people, the bench press, the overhead press can actually be performed with less risk to the shoulders.