You'll also find some answers (including mine) at this recent Stack Overflow question.
My must-read list includes:
- The Non-Designer's Design Book
- The Elements of Typographic Style
- Designer's Color Manual ad/or Light and Color in Nature and Art
- Almost anything by Wucius Wong, particularly Principles of Form and Design
- Meggs' History of Graphic Design, and/or Graphic Design History by Steven Heller
- The works of Edward Tufte
- Information Architecture (Rosenfeld)
- Designing Interfaces (Tidwell)
- Be familiar with Jakob Nielsen's work but don't let it run your life
- Michael Angeles' website, urlgreyhot
- Khoi Vinh's website, Subtraction
