Code Complete: A Practical Handbook of Software Construction, by Steve McConnell
This was a great book. If you have been in software for a significant time you are likely to have picked up many of these habits already, assuming you have been around experienced engineers who have helped you cultivate your software capabilities. It is chock full of useful information that every engineer should know. While this is a sure career improver for new engineers it has information that could easily be digested and used by even the most experienced programmer.
Seminal book. Buy it.