References and resources for every WordPress developer

• WordPress Codex
• Actions and Filters Database
• Core Developers Blog
• Core Bug Tracker (trac)
• Core VCS Repository (subversion)

Developer tools that I use daily

• git – source control is a must.
• Transmit — rock solid FTP/sFTP client.
• vim and mvim

Books*

• Code Complete: A Practical Handbook of Software Construction
• Clean Code: A Handbook of Agile Software Craftsmanship
• The Design of Everyday Things
• JavaScript: The Good Parts
• PHP Objects, Patterns, and Practice
• The Pragmatic Programmer: From Journeyman to Master
• Pragmatic Thinking and Learning: Refactor Your Wetware (Pragmatic Programmers)
• Professional WordPress Plugin Development
• Pro JavaScript Techniques
• Refactoring: Improving the Design of Existing Code
• Web Operations: Keeping the Data On Time

Other Resources

• Vimcasts

* Links to books that I recommend use my Amazon affiliates code.