Second Life is remarkably free of them, for example), nine times out of ten endgame content will at least peripherally involve someone tanking something big and nasty. Usually with claws. And in almost every case, tanking involves a series of mechanics about threat. There has to be some reason why the big nasty is targeting the character in four-inch-thick armor with a shield instead of the robed priest that has a coughing fit when she walks too quickly, after all.
For the upcoming expansion, World of Warcraft's team is considering making some changes to threat mechanics, something that Spinks summarizes and rails against quite eloquently. It does raise the question, however, of how responsible a tank ought to be for managing threat. How big a part of gameplay should tanking actually be? Do you prefer games where you never have to worry about threat, or games where tanking is a very near thing? Which game do you think featured the most engaging methods for holding enemy attention that you'd like to see more of?