If you are married, I think it is an excellent idea for your spouse to come along...
spouse is appropriate absolutely....
parents, still no.
Absolutely. Anyone who is making that big of an investment in your future deserves to see what you are getting yourself into.
I would tend to agree, but only to a point.
These are professional programs, and you have to come across as independent and intelligent IMO. Having a parent or spouse tagging along is also somewhat disruptive in a group interview where some applicants have a guest and some do not. How are the applicants supposed to ask candid questions of students/admissions when Timmy's mom is there? Some parents/spouses are also overly agressive and can compete for the attention of the tour guides students/admissions staff, etc.
I think it's a lot better for an applicant to
privately bring their spouse, parents, etc around the campus before or after your interview (probably after, so that you can help inform them). The lone exception might be if you're the only interviewee on your day or there's a purely social part of the interview (lunch/dinner after the conclusion of interviews, etc). That is a more acceptable place for your guests IMO.
As an example, I'm sure not gonna have my wife sitting beside me... or out in the waiting room, during residency interviews. We will surely discuss the pros/cons of the programs, she will visit the city/hospitals I'm considering, etc. You have to draw the line somewhere, though. I didn't have my parents sitting at my pod school interview or lunch either... I'm a big boy.
For the interview, as was said, dress like you are running for senator: neat and conservative. Related discussion:
http://forums.studentdoctor.net/showthread.php?t=423628