Hi Paul,
Head First JavaScript does not cover any IDEs or development procedures (other than promoting best practices in general).
We like to say you can start programming with a simple text editor and a browser, and I do all my coding that way for the book so I know how it will feel for someone programming that way.
That said, yes, there are some good tools emerging that will aid in development. I have heard good things about WebStorm although I haven't used it myself yet; I primarily use TextMate and Coda. It's certainly true that once you get used to a certain tool, it takes effort to change!
I'm sure others will chime in with their tools and processes.
I'm curious how many people use
unit testing with JavaScript. This is an area I'm just starting to learn more about.
Elisabeth