Definitely not! Say it! But be genuine and eloquent - which should not be a problem for you, DrD! If you are in love with a school, I really think it's important to be detailed in your reasoning (i.e., what about the curriculum, educational methodologies resonate with you? What about the location? What about the patient populations?). The job of an interviewer (in most cases) is to serve as your representative when your file goes to the committee - if your interview has more concerete examples - which you provided him/her with - as to why you are a good fit for the school's program and why you are paricularly excited about attending said program, it can only help. IMHO, of course!
Granted, at a top 10-15 school, I don't think this process holds THAT much weight - after all, doesn't everyone want to go to Harvard, Hopkins, Yale, Cornell, Columbia, etc.? Still, if you have unique reasons (I'm interested in pursuing research with Professor X; my sig other goes here, etc.), it might help you stand apart from the rest of the well qualified crowd...