Bill Verplank caught my interest on a number of levels. His simple framework for looking at Interaction Design, in the book Designing Interaction. Sketching while he presents information – to name a couple…This video in the book designing interactions has an extended lecture available – IxD >http://vimeo.com/20285615
Bill says that the interaction designer needs to answer three questions, about how people act, how they feel, and how they understand. He illustrates the answers as he talks.