Personas: Personalize the look of your Firefox by selecting new themes called Personas in a single click and without a restart.
Plugin Updater: To keep you safe from potential security vulnerabilities, Firefox will now detect out of date plugins
Stability improvements: Firefox 3.6 significantly decreased crashes caused by third party software – all without sacrificing our extensibility in any way.
Form Complete: When filling out an online form, Firefox suggests information for fields based on your common answers in similar field.
Open Video and Audio: With the world’s best implementation of HTML 5 audio and video support, now video can be displayed full screen and supports poster frames.