A Great Information Resource on SQL Server 2005
The first book writen by Kalen Delaney I read was Inside SQL Server 2000. It was by far the best book on SQL Server 2000 that I have read. It gave me all the information on SQL Server 2000 internals I needed, and a great deal of that information was not covered anywhere else (not even SQL Server Books Online).
SQL Server 2005: The Storage Engine contains the same type of information for SQL Server 2005. You can learn a lot about databases, indexes, transactions, locks, recovery and SQL Server internal architacture by reading this book.
The book is clearly writen and is packed with useful information. I would recomend reading it to anyone who is serious about learning to work with SQL Server.