All the Ivy League schools (Harvard, Yale, Dartmouth, etc.) either require or recommend an interview before your application is approved. There are some other schools that require interviews and others that offer them as an option. Having said that I would personally recommend taking an interview. It is a valuable opportunity to demonstrate your interest in a school and seize the opportunity to present yourself in a positive light. I was preparing for my interviews with a few top Universities and iSchoolConnect helped me a great deal for the same. Check them out here - www.ischoolconnect.com