Mozilla Firefox
a free, open-source web browser for Windows, Linux and Mac OS X and is based on the Mozilla codebase. It is small, fast and easy to use, and offers many advantages over Internet Explorer, such as the ability to block pop-up windows.
Mozilla ThunderBird
a free, open-source and cross-platform mail client for most operating systems including Windows, Linux and Mac OS X.
Opera Web Browser
fast, lightweight and free web browser, IRC and e-mail client.