A recent post by Steve Makofsky reminded me that the excellent UI Patterns and Techniques site is now a book from O'Reilly -- Designing Interfaces.
There's technically no reason to buy a book on visual design patterns when you can find the same information online ..
.. but what a glorious, infinitely browsable full-color book this is. It's highly visual and truly does justice to the concept: a Design Patterns for the eye instead of the mind. Sometimes atoms are better than bytes.Unlike any of the Design Patterns in that famous book, these patterns are visible to your users. Plan accordingly.