Oprah says "Live your best life" and this book is practically an instruction manual on how to do exactly that (not that he quotes O...but the plot pretty much explores this question in detail.)
You've seen the number of reviews already so I'll just say to my friends...yes, read it, and NOT ENTIRELY because he loves Thoreau, either. For everyone who ever thought about regrets in any way other than Sinatras "too few to mention"...this book is worth reading. If you dream about your high school sweetheart with "if only" in your mind, this book is worth reading. If you want life to be a "do-over" as in the "Sliding Doors" or "On a Clear Day" movies, or in the "Communicating Doors" play, read it.