I heard from a friend recently that went on an interview, and had done some research beforehand. This person jotted thoughts and questions in a notebook, took it to the interview, and made notes as the session progressed. I had never done that, but it makes sense, and I think I'd do that in the future.
I also typically take notes when I'm on an interview. On one interview, I actually made notes on the way home (on a train, not driving) for the company's recruiter. When he called the following week for my feedback (and, as it turned out, my decision as to whether or not I wanted the job), my first question for him was "Do you provide interview training for your employees?" We then spent about another 30 minutes discussing what their interview process was like. At the end, he thanked me, and then asked "I get the feeling this question is redundant, but, the group wants to hire you. Are you interested?" We both had a good laugh at that point, as I turned him down.