Hi yyd,
When I get that question, I already have told the interviewer most of my qualifications, and the admissions comittee will have my AMCAS right in front of them. I just ask my interviewer to tell the adcoms how honored I am to have been invited for an interview, how excited I am about the school, and how much I want to attend (i.e. "I would be so happy here" or "This programs fits me" or "This is my DREAM SCHOOL"). I think that gets more across that isn't already there on paper.