If you could recommend a single book that made you a better PM, which one would it be?
The One Minute Manager Meets the Monkey by Kenneth Blanchard -- http://www.amazon.co.uk/One-Minute-Manager-Meets-Monkey/dp/0007116985
They aren't explicitly PM books, but after being in a situation where I was in a minor leadership position and seeing problems in communication, these books really changed the way I approach handling conflicts in a team setting.
Its Amazon reviews make it sound more like a management book than a PM book, but if Project Management is "making things happen", then this is the best introduction to the subject I've ever read. It'll only take you an evening or two to read, and then you'll need to look elsewhere on this list, but if you're just getting started then this is the first book you should read.
I enjoyed Project Management for Dummies. Though it may not be the kind of book you see in a classroom setting, I find with subjects that can be as broad as this one, usually the class or setting is more of a survey rather than diving deeply into specific aspects. For that reason, I think this book does a good job giving an outsider, or someone looking to step into the role, the information needed to have an understanding of what is expected of the manager, the team, the process, etc.
Quality Software Project Management is the best project management book I have every read. It covers all the competencies needed for PM and it's relation with quality and process frameworks like CMMi.
It solely depends upon what you want to learn, if you are learning process/phases/document involved in a project then I recommend you to read PMBOK, but if you want to go for the qualitative analysis of each/small part of a project then you should read books written by various writers on project management. One of my favorite is "Employee First Customer Second", it tells the importance of keeping employee happy to reach the zenith. Project management is a vast field and you need to decide where to start from. It's a on going process and will be continue till the last day you practice project management.
I really like The Art of Project Management by Scott Berkun. This gives a good real world overview of how to manage software projects. It is very readable and quite different from a standard project management text book. I think Scott has published an updated version called Making Things Happen: Mastering Project Management which brings things a little more up to date.
I would recommend you to take a look at this website It helped me a lot to manage projects. Not only just downloading and reading ebooks, but also learning from video tutorials. It also provides trial tools for project management.
Personally, I really like The No Asshole Rule by Sutton. While it won't tell you how to manage, if you execute in an agile atmosphere, it helps in setting up teams that can execute (and companies).
For more straight how to run a project, I like Succeeding with Agile Development by Cohn. Obviously an agile book, but one of the better I have read and good advice on how to move teams and get them to adopt culture change as well.