Firefox
Mozilla Firefox is a web browser software program.
It is fast, secure and customizable by allowing you to add small pieces of software called add-ons.
The default website is here : http://www.mozilla.com/en-US/
The add-ons page is here : https://addons.mozilla.org/en-US/firefox/
Don't forget that firefox is absolutely free and only 5.7MB for version 2.0.0.3 for Windows.