Designing Web Navigation: Optimizing the User Experience by James Kalbach, published by O'Reilly. ISBN:0596528108.
This is a book about design, not implementation. You may have grokked that from the title... The book's beautifully laid out with lots of shots of real websites scattered across full color pages to help illustrate important points.
The first chapters are pretty academic and can be pretty dry, but they provide good information on content/information architecture. The rest of the book is an easier read, but that doesn't mean you should skip the first chapters. Lots of good sidebars call out specific topics -- accessibility is a hot topic throughout the book and gets a lot of sidebar treatment.
The book's full of gems such as how you should consider workflows in navigation (think shopping cart systems, e.g.), or the differences between "lingo" and vocabularies. There are also a bunch of great references to other works, and each chapter has some nice exercises which are actually pertinent and helpful in making the reader more aware of that chapter's points.
I was surprised that globalization/localization didn't get more treatment in the book, but there are quite a few example screenshots and discussions around international websites.
Overall it's a very interesting, thought-provoking book.