The first chapter in the book covers C# 2.0 and the book is very much worth buying for this chapter alone. Features covered by the chapter are as you would expect: Generics, partial types etc. We have been hearing and reading about them in the MSDN magazine for over a year. Still, it was very useful spending a couple of hours reading this chapter and nailing down each topic. It was also great to see the new covariance support for delegates covered, which I imagine is included to keep us hardcore happy.
It was a shame to spot a simple technical error: the book states that static classes cannot have a constructor. How this was not picked up proof-readers I have no idea. Just in case the CLR team has started taking mind altering drugs while designing 2.0, I knocked up a quick sample with a static class + static constructor and it worked fine.
So on to the rest of the book. Well there are lots and lots of page filling screenshots covering the new Visual Studio, WinForms, WebApps and Data Binding etc. These may be of use to less experienced developers, but I would have preferred simple short sections covering new features. Walking an experienced developer through how to setup a masked text box (>4 pages!) was not useful to me.
Summary: If you are just about to embark on your first .Net 2.0 project I recommend buying this book first chapter alone. It won't take long to read, and then you can pass it to another team member. I do expect this to be a book you will use for reference.