How the hell did I miss this thread?
I swear by How to Brew. It remains my main technical reference in an increasingly impressive library of Beer and Brewing books.
Full of really cool, in depth technical knowledge, Principles of Brewing Science by George fix is a must for the brewing ubergeek.
For recipes I actually quite like Brewing Classic Styles. Not that I actually follow any of the recipes, but it gives me something to look at and disagree with.
For someone looking to start out in brewing my advice would actually be, don't buy a book yet. Books have lots of information you don't need to worry about for your first brews. Instead I would point them at our Knowledge Base and articles like Barry's illustrated guide to extract brewing and my own getting started brewing beer with kits.
Once they have the basics down, the more technical aspects won't seem so daunting.