"Don't make me think!", the title and the book are extremely useful when designing a UI.
Some of my favorite sections from it include:
- Create a clear visual hierarchy.
- Conventions are your friend.
- Happy talk must die.
- Instructions must die.
- Four reasons why I love tabs.
- The trouble with Rollovers.
- Farmers vs. Cowmen.
- The myth of the "Average" user.