I understand your reticences at buzzwords and promotionnal catch lines (those marketing guys are really something, aren’t they

?), but still I have seen Fred’s work and usability isn’t all smoke : it’s part common sense and web experience, but there are also knowledge areas (studies which range from eye-tracking and how humans perform various cognitive task on the web...etc) and methodological aspect (like user cases) which can really give some insight that you couldn’t get on your own.
I mean we can’t master all aspect of building web sites and web applications. There is a lot to learn from IA guys, HCI specialist and usability is one area of expertise where there might be few real experts (the others just surf the trend), but they do have added value. Right now, if you take the
cms-uig work, it’s just starting (see their
wiki) but it’s certainly commandable to try to think about ways to enhance web application’s usability.