As tough as the question is, this is something that you really should address, regardless of whether it's for the interview or not (as in, when you have an acceptance and are deciding if you want to go).
At the interviews I have had so far, I am getting very positive responses when I respond with novel thought regarding how the school as a whole fits with my peronsality, ability to learn, and potential happiness. The plain truth of all medical school is that they all grant MDs. What sets each of them apart are:
1) Curriculum
-Things like class time, didatic vs. group learning, clinical exposure, overall interest level that I can gauge from faculty during the financial aid/welcome presentations before going into the actual interview are all important things that I take note of so I can answer the question of "why this school".
2) The Students
-Are the happy? Do they feel like the administration pays attention to their concerns? Are they given a lot of stuff to do during the 3rd/4th years or are they on the sidelines doing scut? Do they have free time to keep themselves balanced (this was important to me - I need a very balanced life)?
3) The location
-Safety, of course. Affordability of the city, access to cultural events, access to a gym or recreation center, undergraduate campus, sporting events, intramurals, etc.
For me, I found it easiest to decide on what my ideal situation was as far as these criteria go, and then see how each individual school compared. Of course no school was going to be an absolutely perfect match, but when asked "why X medical school", you can have an idea of the specific reasons. If I were the interviewer, I would not be very impressed with "I think I can be happy here" or "X school has a great reputation". I think they are really seeing if you've put the time into it.
Just my thoughts - I hope it helps someone
