Bob Sutor made some good points in his article entitled "
Saying it out loud: IBM is moving to Firefox as its default browser":
http://www.sutor.com/c/2010/07/ibm-moving-to-firefox-as-default-browser/

"Some of us started using it because it was new and fast and cool. I tried it for those reasons, but I still use it for the following ones:

* Firefox is stunningly standards compliant, and interoperability via open standards is key to IBM?s strategy.
* Firefox is open source and its development schedule is managed by a development community not beholden to one commercial entity.
* Firefox is secure and an international community of experts continues to develop and maintain it.
* Firefox is extensible and can be customized for particular applications and organizations, like IBM.
* Firefox is innovative and has forced the hand of browsers that came before and after it to add and improve speed and function."

I would add that with Ubuntu 10.04 Linux equipped with AppArmor and a preconfigured standard LSM profile for Firefox, there is no comparable browser for a safe internet experience. Unlike Windows, AppArmor LSM sandboxes the FF session so there is no possibility of Zero-Day attack escalation.