I'll start with two questions: 

1. Have you ever used the devel module's dpm() function?  2. Have you ever used a PHP debugger with Drupal?

If you answered "yes" to the first question and "no" to the second, this post is written for you (and if you didn't, well, you can probably skip it).  I have a hunch there are lots of you out there; I'd certainly have answered that way myself for far longer than I care to admit.  Suffice it to say that my debugger is now a tool that you'd have to pry from my cold, lifeless fingers.