Today, let's look at some more practical books from the shelf.
Network Algorithmics, George Varghese: Even before he wrote this book, George Varghese had essentially written the book on how to get good performance on your network devices (e.g., routers) by smartly using algorithms combined with systems thinking. George is my role model in this area, even moreso now that I've worked with him on a few projects. If you want to see how network people are thinking about and using algorithms for packet classification, prefix-lookups, switching, scheduling, security, and so on, pick up this book.
Mining the Web, Soumen Chakrabarti: Sigh. Has it really been over ten years (no need to get more specific than that!) since Soumen and I were graduate students at Berkeley together? Soumen's one of those people who could have been a great theoretician, but was always lured by that "real world" thing, and instead became an expert on information retrieval and the web, which lets him still do theory now and again but with an eye toward problems of more immediate importance. A great book for everything you might want to know to start building your own search engine. Web crawling, information retrieval, clustering and classification, etc. And lots of algorithms and algorithmic insights.
TCP/IP Illustrated, Volumes 1 + 2, Stevens and Wright: At some point, I was looking at TCP for research purposes, and this was a great book for understanding the fine details. It may take a little looking, but the details are in there. Volume 1 also provides background on a lot of basics that I think are useful for networking research. Finally, I also think it would be useful for theorists to look over this book at some point is to get some insight into real-world systems-thinking.