My favorite rule is 4.1.1; always use braces even where optional. I think a small fraction of the economy may have been damaged by the bugs caused by the silliness of leaving out optional braces and then having another developer come along and, well, you know how that goes :)

As someone who once read the Sun Java Style Coding [1] (which at a quick glance, appears to be a super set of the Google style guidelines) standard years ago and found it exciting and very helpful material, I unfortunately did not get such a kick skimming through this. Perhaps it's because after having read Clean Code [2], I feel that there is much missing that can lend itself to better code.

[1] http://www.oracle.com/technetwork/java/javase/documentation/...

[2] http://www.amazon.com/Clean-Code-Handbook-Software-Craftsman...