Unless you happen to know that your field or the institution at which you are interviewing is rather formal and is festooned with people wearing suits, you apparently can't go too far astray by wearing comfortable "business casual" attire. As I hoped, commenters seem to agree that there is a wide range of acceptable professional garb, so everyone (men and women) should be able to find something in which they feel comfortable, confident, and unselfconscious.
In the following fields, at least one commenter cautioned against wearing a suit as "overkill", especially with a tie (men), or noted that you will look like a sales rep (men) or administrative assistant (women), and that's not good:
- BIO-EVERYTHING (CHEMISTRY, ENGINEERING, MED, FIELD, GENETICS, INFORMATICS)
- EARTH SCIENCES
- ASTRONOMY (but see comments and list below for indication of lack of agreement)
Speaking as an old(ish) professor who has seen many interviewees wander through my departments over the years, I can say that I don't notice what interviewees or any visitors are wearing (men or women), with the exception of the woman whose feet were bleeding in her uncomfortable new shoes. In that case, I only noticed because she kept slipping the shoes off.
It would be great if others continue to comment and provide more data, but can we now consider this pressing issue mostly dealt with, resolved, sufficiently addressed, and/or defanged, at least in this corner of the blogosphere?