FireFinder: Makes it quite easy to verify that the selector values in your code are correct and that the proper elements are returned. I was able to immediately pinpoint problems with my selectors and this brought to light why certain events were not firing.
Firebug Console: Using the console.log function allowed me to check values without littering my code with alert statements.
FireQuery: At a glance this plugin for Firebug shows which elements have event handlers bound to them.
Thanks to the author of the article, Elijah Manor, for the in-depth information on debugging jQuery code.