I just finished reading Designing Social Interfaces. The book is written by the creators of the Yahoo! Pattern Library. I had no knowledge of any such pattern library previous to reading this book, but I've really been exploring the idea of creating user experiences on the web that will bring in users and keep them happy (and not confused). I think a lot of this interest has to do with Canonical's current focus on design and usability.
The book is an O'Reilly book, but once it's opened, it certainly doesn't feel like an O'Reilly book. The pages are slicker than normal O'Reilly books (and I own many of them). They're also in full color. This is great for a user experience design book, since it's often hard to look at screenshots of web sites when they're in black and white.
I soon realized that I was fascinated with the book itself. When it comes to web design, there are a few staples (Don't Make Me Think comes to mind), the books don't seem to be specific enough. They usually just show good examples, but they don't show the why of the good examples. Designing User Interfaces starts with the why, which is something I can really appreciate.
As a developer, I also have a tendency to think in "design patterns." By presenting the interfaces as "patterns," it was easy for me to start thinking up my own variations of those design patterns to work with my existing experiences and products. This is probably what sealed the fate of this book. It made me excited to re-design and re-think interfaces I've implemented (including Launchpad).
I would highly recommend this book for anyone doing front end work, whether it's just implementing existing designs or creating your own designs. I've noticed that I now critique web interfaces with an eye I didn't have before I read this book.