I picked up Perl Best Practices the other day. I'm quite impressed, even as I (surprise!) don't necessarily agree with all the recommendations. I like the explanation and illustration with each one. It's not just a list of "do this" and "don't do that". It has meat.
I like the helpful bits such as the perltidy settings to implement the formatting suggestions, and the editor configurations for vim, vile, Emacs, BBEdit, and TextWrangler.
I highly recommend this book...