Mastering Exchange Server 2007 book - Feedback requested

Sybex/Wiley has asked me if the Mastering Exchange Server 2007 book should be revised. I am looking at what should be included if the book is updated for a 2nd edition. If you own or have read this book, I would like to hear from you. What should be added, removed, supplemented, improved, etc... in this book. Please contact me at jim (at) cta.net