Framework Design Guidelines is a gem.
If you haven't read this book yet, you really should. This book gives you a lot of insight into the "why"s, something which a lot of standards documents are missing. It's one thing to be told to do something in a particular way, but it's a lot better when you are told why. Simple coding patterns that I wouldn't have given a second thought to have turned out to have a great impact on other aspects of my code once they were explained.
The basics are covered, such as naming and formatting standards, but the book goes much further with sections about when and how to use certain interfaces, and provides some brief explanations of common design patterns as they relate to the .net framework. I'm not talking about "Visitor" or "Model View Presenter" here, I'm talking about "IDisposable"... muuuch lower level stuff.
Basically, this book isn't just about what you ought to be doing, it's about explaining why Microsoft did what they did in the .net framework. It's refreshing at times in the book to find a discussion about how something was a bad choice in retrospect, or how the framework designers wished they had done something differently knowing then what they know now. I feel a lot better about my own changes of mind, and less like an amateur for not having seen the eventual solution in the beginning. After reading it, I'm more comfortable that I've made the right career decision to stick with this programming stuff.