On one of my first interviews out of college, the interviewer looked at my resume and said "I see you were in a sorority. So what, you can't think for yourself and had to be a lemming?" I'm not sure if it impressed or shocked him when I mentioned that I was a founding member of the group, so rather than following, I was a leader. Did not go back for a second interview there.
I never appreciated it when interviewers seemed unprepared to answer questions from me or worse, gave me vague responses that didn't really answer the question. A harbinger of the type of employer, I suppose.
As for some of the best questions, I appreciated scenario questions like Bill mentioned. It gave insight into the employer and the types of situations, and gave me the ability to show what I could do rather than what I could talk about.