Professional SharePoint 2007 Development by John Hollidayet is a book I would recommend.  An excerpt from the Foreword sums up the book nicely:

"The authors cover the breadth of SharePoint without sacrificing the depth you need to understand how to build complete and robust SharePoint solutions. In fact, you will find yourself consistently reaching for this book on your bookshelf, earmarking pages that have the tips and tricks you need to get your job done, and this book will quickly become an indispensable part of your SharePoint reference set."

I'm only on Chapter 4 : WSS v3 Platform Services and have created a Site Definition that I can use to deploy my application - more importantly I understand the process.   I would be careful not to skip over any of the early content as there were a few paragraphs that had I missed them could have had me chasing my tail.

My SharePoint Development Site: http://Dev.Global-Webnet.net/SDMS