I really enjoyed this book, although parts of it annoyed me. It's an interesting approach on life, and a definite wake-up call for people who work too much. Biggest takeways:
1) The notion of "deferred life" - what you're basically doing if you're working hard for the sake of a comfortable retirement.
2) If you were retired right now, what would you be doing? How much would it cost? The types of things that are really important/interesting to you might not even be that expensive.
3) There are a lot of creative ways you can cut back on work without cutting back on income. You waste a lot of your day working on things that aren't important.