Shazman said:
...the assumption that competent equals overpowered.
The issue to me, as to whether a game I'm in is overpowered or not, is if the PCs abilities and aptitudes (Skills, Feats and Ability Scores) are overshadowed by the presence of an ever-growing magic item list. For instance, we can look at the four characters indicated earlier as examples of "heroic" characters the game attempts to emulate.
Luke Skywalker: The Force is potent, truly without limitations. However, there are lines that should not be crossed else one steps into "the Dark Side". Equipment wise, he had one Light Saber, which, while also potent, is not the be-all of armaments.
Aragorn: A magic blade that likely can't be translated into D&D terms very well. Beyond that, it was his specialized training as a Ranger (Herbalism, Healing, Woodslore, etc.) that got them through most of their travels.
Jack Sparrow: Wit, charm and cunning. That's it.
Buffy: Alright, I don't follow the series, and only caught the end of the movie, so I'm not all that familiar with it. However, it does seem that she is also the opposite of a D&D "hero" in that she, as "The" Slayer, is a unique individual and thus not likely to produce an "adventurer's economy".
I think you can see what I'm getting at here; D&D no longer even pretends to emulate such characters or adventures, but rather assumes that every character requires an ever-expanding pile of magic items dumped on top of it, a pile that quickly over-shadows any measure of competance that the character may actually have in a growing morass of bonuses from outside sources.
I want my character to shine for the deeds that got him his treasure, not for the treasures that do the deeds for him.