I have a purist approach to database design and modeling but I was totally blown away when I read Len Silverston's
The Data Model Resource Book
A Library of Universal Data Model for All Enterprises
If you want to have a totally different perspective in modeling and designing databases, then this is a must read book.
I know this is a SQL Server forum but I was an Oracle DBA in a past life and Oracle is still near and dear to my heart, with that said, one of the best books I've ever read on database development for Oracle was Thomas Kyte's:
Expert Oracle Database Architecture: 9i and 10g Programming Techniques and Solutions
I think the concepts and solutions that were provided in this book is applicable to any type of database development effort and the underlying message (dispelling rumors and hearsay by testing and supporting facts with data) that Tom had resonates across all types of technological endeavor.