My interviews were laid back and fun, mostly, but if you want a hard interview look no further than the Mayo Clinic. Their behavioral interview consists of 5 or so specific questions about situations where you've had to deal with/done X. I had several general stories prepared, but their questions were specific enough that I couldn't shoehorn them and had to come up with new experiences on the fly. I should really have tried harder to shoehorn the good stories, but oh well! I tried my best. Here's a lesson, though- I thought I did terribly and didn't stand a chance, but I got in!
Emory was 3 interviewees and 2 interviewers. Went round robin then a few open questions. I had a bunch of answers prepared but should have memorized them a bit better. Ruffling through my notes was a bit distracting, I think. The key in these is to listen to the other interviewees and build off what they say. "Similar to what she mentioned, I also think that..." and, if you think differently, "I hadn't thought of that before, but that's a really compelling answer. My first thought on the question is that..."
Prepare with online question lists, but once the time comes, relax. By the time the interview happens, you've already done all the work you can realistically do for it and the rest is just relying on what you practiced. It's already over, as far as you're concerned, so just relax and be friendly. Most of the day is them trying to sell themselves to you, while only a few minutes is you selling yourself to them. Remember that they're trying, too, and you're not desperately trying to fit where you don't belong. You already do belong, otherwise they wouldn't have invited you. Now just chill and have a good day, making friends where you can.
I wore a black pinstripe suit (small pinstripes, yenno, not full-on gangster) and blue blouse. Blue tends to be associated with friendliness and warmness, and I already had the black for a professional impression. I either came across as laid back but professional or a well-dressed bruise. I also had a black leather portfolio with notes in it to write and put any papers they gave me in it.