Mattachine
Adventurer
I would say providing classes with strong archetypes has been long been one of the central draws of D&D, its also one of the things that engages new players the most. New players know what a fighter, or a mage is and can understand there place in the game MUCH more then in classless roleplaying systems that allow players a high degree of customization (like GURPS or even Rolemaster). These systems have been around for a long time, but the archetype class system has been very successful (e.g. its present in most online rpgs)
Though we disagree on much, this I agree with. One of the things that makes D&D "feel" like D&D is strong archetypes. As someone who runs an RPG club at a school, strong archetypes attract new players and make it easier for them to begin to roleplay.
Still, strong archetypes do not have to enforce classes that are only good in one or two of three areas.