ask about match data, reputation of the school with residency directors, how well the students at your institution do at matching in an area of medicine you are interested in, student cohesiveness, opportunities to shadow doctors during your first year, stipends for research, international opportunities, etc.
whatever you do, don' t say no if they ask you if you have any questions.
I think it's great to ask questions based on WHO the interviewer is! My first interview, I went in with these pre planned questions I was going to ask- but had no idea I'd get a surgeon as an interviewer. Well i ask about curriculum or reputation and he's like- -well i don't keep up on that.
Point is- INTERACT with the person. Not with the school.
If you have a Doctor- one question I ask is, "you've worked with residents and medical students, how do you feel the students from xyz school are trained here?
Turn the tables a bit - and ask him about health care- ask him what he believes is the greatest issue in health care. And if he could change one thing in the medical field what would it be. Doctors love to talk and to have their opinions heard. And you can seriously learn alot at the same time.
so go in not with general questions- but questions for whoever you might think may interview you.
Dean, Student, Surgeon, Research doctor, Faculty, ...
also a good one is, what's your typical schedule like (if the guy does research) .. how much clinical time do you put in as opposed to research time.