Learning to program in C is easy. It's learning to debug C programs which is hard.
And, of course, learning to write programs that other people can read and debug.
In general I agree with Therem Harth on this one: Kernighan and Ritchie is still the way to go. Except perhaps if you're going to be writing code where security is critical. K&R example code is often overly trusting of user-supplied input. I once mentioned this to Brian Kernighan, who told me that they had been aware of that even as they wrote it, but that in the computing environment of the time it didn't seem like a big issue. Fortunately for most of the things I do it still isn't much of an issue.