This is an impossible question to answer. There is general agreement about some things, but for the most part everyone has their own set of resources to suggest. Maybe one day you will have your own.

My standard set of recommended books, in order of my preference for actually learning the breadth of Perl, are:

1. Object Oriented Perl (Conway)
2. Effective Perl Programming (Hall, et al.)
3. Mastering Perl (brian d foy)
4. Perl Best Practices (Conway)
5. Perl Medic (Scott)

>Perl the correct way

No book will teach you this any more than a book on a Human language will teach you how to speak or write the "correct way". Writing Perl, studying others' Perl, and participating in the community will be your best guide here. Same with any language, immersion is the best path for achieving the proper levels of enlightenment. There is a tremendous amount of free information out there. I encourage you to:

• read standard perldocs
• read module POD
• read internal source code of the modules you use
• read the resources listed in Perl News
• watch the countless YAPC, TPC, and Perl Workshop videos on ewetube
• lurk/participate here

Advanced Books I like:

1. Higher Order Perl (Dominus) site
2. Practical Text Mining in Perl (Bilisoly)
3. Perl 5 Internals (Cozen) pdf
4. Perl Testing: A Developer's Notebook (Langworth)

Milestones of Personal Development (no order, but everyone needs goals):

• ask questions on Perl Monks
• answer questions on Perl Monks
• locate your local Perl Mongers group
• actually attend a Perl Mongers meeting
• become a CPAN author
• contribute to someone else's CPAN module
• get into an argument on p5p about an aspect or change in Perl you're passionate about
• get banned from p5p due to overzealousness xD

One final note I will add is that one does not simply learn Perl. The best way to learn it is to use it to create something. Anyone that is passionate about accomplishing something with Perl will learn it along the way. So the best marker for success is having a motivating project or application of Perl to achieve. If you don't have one, think of one or find a project to get involved in. Good luck!