Having been through a few job interviews in my day, I can say that this is one of the most challenging questions to answer. How much should I say? What should I include? Most importantly, what should I exclude?
As an interviewer now screening candidates, I can say that I don't put that much weight on the question as this piece implies. But I do still ask it, usually as a way to relax the candidate. In fact, I'm usually more concerned with how a person carries them self in the interview - how they act, their demeanor, and most importantly their sense of humor (or lack thereof). Most skills can be taught, but personality is a priceless intangible.