It is clean and simple, more secure than Microsoft Internet Explorer, and its functionality can be easily extended and customised.
Allows offline access to web services that support it.
Including: Google Docs, Google Reader, Remember the Milk, Zoho Office
Google Notebook Extension
Gives you easy access to Google Notebook.
Integrates Delicious' tagged bookmark system into Firefox.
Integrates Diigo's bookmark and comment system into Firefox.
Remember the Milk Gmail extension
Puts a to do list next to your mail in Gmail.
Lets you organise your email with GTD, David Allen's Getting Things Done system.
Lifehacker "Better" Firefox Extensions
- better gmail2
- better gcal
- better greader
Automatically loads the next page of a site while you are scrolling.
Looks promising, but crashed Firefox for me. Perhaps it's not compatible with one of the other extensions.
Multiple html signatures per google account.