The Big Boss Man: End Bosses and Narrative

Barnes mentioned something recently in the forums about either not liking or being tired of the "big boss" syndrome in games. It really struck home with me as it dawned on me that this is something I really, really like--and the notion of having a "boss" to fight often makes a game more enjoyable to me. It's exciting, and conducive to an emerging narrative. It gives players a goal, something to ramp up for, something to accomplish. Sure, it can be a tired, cliched device as well, as so many action movies feature a lead villain, a nefarious end boss that the hero has to overcome and save the day.