This should, of course, be subtitled "Books Not To Read If You Are Me." These aren't necessarily bad books (in fact, both of them are good books) but they weren't that useful to me or to people in exactly my situation. Take this with as much salt as you feel appropriate, depending on what you're working on.
The first is "Getting Real: The smarter, faster, easier way to build a successful web application" by 37signals. If you're doing web-application development, I'd say this is a book you should read. I'm not doing that, and thus, didn't see a whole lot of value here. I'm making a mental note to reread this if I ever do get into a web development project, and it did make me think about ways I could make our current development procedures more agile -- but if the question is "Was this worth the time it took for me to read it?" then the answer is "No."
The second is "The Mythical Man-Month: Essays on Software Engineering, Anniversary Edition (2nd Edition)" by Frederick Brooks. It came highly-recommended in every software management book I've read, so I figured it had to be on my list. While there is much still of value in this book, easily a third to a half seems completely out-of-date -- advice on whether to use printed manuals or microfiche that seems as applicable as a discussion of which tools are best for shoeing horses.
While the concepts discussed in TMMM were clearly revolutionary, I'm not sure it makes the first cut for a software management reading list today. If you're studying the history of project management, then you must read this book. It's a classic in the field. If you're just trying to be a better manager today, most of the ideas it contains are captured better in other, more current books, particularly "Peopleware," "Joel on Software," and "Managing Humans."