Much of what we've covered here is quite subjective, so it's hard to recommend books because any book (including this one!) that claims to have the final say on a topic such as formatting your code is clearly one can short of a six-pack.
Having said that, I'd like to take this opportunity to recommend (again) Fred Brooks' excellent book, The Mythical Man Month, as it's a very practical text book on the art of programming.
More advanced readers might be interested in Programming Language Pragmatics, by Michael L. Scott. It's quite a hard book, but it really goes into depth in how languages work and why they are as they are.
If this was helpful, please take a moment to tell others about Hacking with PHP by tweeting about it!