It is amazing to me the number of people who don't rank most (if not all) the programs they interview at. Are these programs that bad that they would rather scramble than go there? Frequently the answer is no, they just got cocky. This happens with programs as well. I saw a number of well regarded programs on the unfilled list last year. Did they end up better off by having to accept someone in the scramble or remain unfilled (although the competitive fields generally don't remain unfilled)? Probably not. If they had ranked one or two more people that interviewed there, they could have avoided the hassle. Bottom line rank what you would be willing to take, keeping in mind the alternative may be no match for you.