In addition to the definitive Kernighan and Ritchie, I like O'Reilly's Practical C Programming.
(I got my copy of K&R used for $1 at a Safeway in Portland while getting food for a con. I really can't explain why they had a pile of almost-free used books, or why K&R C was among them. Just one of those mildly weird things that happens from time to time.)