Galeon is a GNOME web browser based on gecko (mozilla rendering engine). It's fast, it has a light interface and it is full standards compliant. [edit]
Datamation has a good collection of 75 Popular Open Source Desktop Downloads posted. The products in the list are categorized, and include business applications, operating systems, collaboration tools, and more. Even if you use a lot of open source applications, you'll probably find some new things to try, such as the K-Meleon and Galeon browsers. Here, below the fold, are a few more useful collections of tools and tips to try.