I read Pointers on C by Kenneth Reek recently. I thought I was pretty well versed in C, but this book gave me a few epiphanies, despite being aimed at beginners. The code examples are things of beauty (but not the fastest code on a x86-like CPU). It provide good implementations of many of the most common algorithms and data-structures that are in use, with excellent explanations about why they are implemented as they are (and sometimes code or suggestions for alternative implementations).
On the same page as your question: patterns for creating reusable code in C (that is what we all want, isn't it?), C Interfaces and Implementations: Techniques for Creating Reusable Software, by David R. Hanson. It has been a few years since I read it, and I don't have a copy to verify what I recall is correct, but if I remember correctly it deals with how to create good C API:s to data structures and algorithms, as well as giving example implementations of some of the most common algorithms.
Of topic: As I have mostly written throw-away programs in C for private use, this one helped me get rid of some bad coding habits as well as being an excellent C reference: C: A reference Manual. Reminds me that I ought to buy that one.
