Well this isn't just for UI design, however I would recommend Designing for the Digital Age by Kim Goodwin (Former VP of Design at Cooper).
Alan Cooper describes it as the ultimate how-to book and I have to agree. It describes loads of methods and provides examples throughout. It goes through all the stages; research, modelling, requirements, framework, and design.
I have used it throughout my second year at university. It was great to understand the fundamentals of a usability method in class and then go to this book and be assured that every single detail would be available.
This book is huge! It is a great compliment to About Face 3 by Alan Cooper.