The Norman reading was one of my favorites because it made me think about something I have never actively studied before. I really enjoyed the topic of representation. How you represent information is incredibly important, but I think its often overlooked (at least I have overlooked it). How you represent something influences how people think about it, which has huge consequences. Depending on the representation the same problem can be easy or difficult.
Taking a class on information architecture I assumed it would basically be about structuring data, but I now believe an equally important task is identifying an appropriate representation for the data based on the users and their goals.