97 Things Every Programmer Should Know, by Kevlin Henny is a collection of CC-Licensed essays containing... well, you read the title! Topics range from beautiful code, to testing and automating tasks, to interacting with customers/clients. Just about every facet of the professional life of a programmer is covered in this book.
As a Senior in a Computer Science program, I found the essays to have extremely good advice. Probably the best essay was the Boy Scout Principle, though they were all pretty helpful. For the seasoned developer, these essays probably won't bring anything new, especially if you've looked into some of the XP methodologies. However, for the novice programmer these principled presented here will hopefully make for a better programmer. The only criticism I have is that while this book is certainly a useful one to have around, though the $29(USD) list price is a little on the steep side ($10-15 seems more reasonable, although I don't know what printing costs these days!)