SWFWire Debugger

An open source AIR application for intense ActionScript 3 debugging, similar to Firebug.
Console tab with Show method entry selected allows you to see a full trace of function calls.

Calls from the fl. and mx. packages are hidden to reduce noise. A search box lets you quickly find the call you're looking for.
The Properties tab lets you view and modify all properties of an object. Even private, protected, and dynamic properties are editable. Dictionary keys show up as buttons, so you can inspect them too.