Firebug 1.5.0
I’m a bit slow of the mark with this one (this post has been sitting in draft for a while), but I just wanted to draw attention to the release of Firebug 1.5.0 last month.
If you don’t already use Firebug (or similar tools such as Webkit Inspector) for debugging your JavaScript, I strongly suggest adding them to your armory. I’m not sure I could survive without breakpoints, step-through debugging, an interactive console, and the ability to inspect and manipulate the DOM. :)

The full release notes for Firebug 1.5.0 are on the Firebug wiki, but highlights include:
- Mike Radcliffe’s Inspector. A key feature, now solid as a rock,
- Jan ‘Honza’ Odvarko’s expanded and refined Net panel, with accurate timings,
- Steve Roussey’s reworking of HTML editing and entity support,
- Kevin Decker’s CSS and Style side panel improvements,
- Support for dynamic, graphical breakpoints through out Firebug.
- Tested support for the soon-to-be-released Firefox 3.6