The Soul of Discipline was a quick read for me since I did his course by the same name a few years ago--really good, helpful, practical material. He really treats all the stages well! I still think Simplicity Parenting was more crucial, but I've also had the luxury of a lot of study and good access to developmentalist thought/courses before this book came out. :)
Goddesses Never Age was a pretty good book too. She can get a little out there, but there was some first rate health information and suggestions.
Getting Things Done was an incredibly practical book. Many of his ideas already came into my space through other people, so I skimmed some parts that were already familiar. I always get into this focus during the Summer since I have the time to actually do things I normally don't get to do.
The Emotion Code is another one of those that might make you scratch your head a bit, but more and more standard medical practitioners are recognizing the effects of these more ephemeral realms. Some of them recognize that energy is a real "thing" if they pay attention to the quantum aspect of matter. They at least recognize things like attitude, the role of nature, placebos etc. So here is one approach to improved health based in emotions and their becoming trapped in our tissue. It's also a how-to for trying to help yourself get rid of them. Lord knows with some of my mysterious health puzzles, I will be adding this to the repertoire.