I am a big fan of Firefox and have been using it as my primary web browser for a little more than two years. The tabbed browsing is a great feature (and one that was incorporated into the latest version of Internet Explorer). Additionally, Firefox 2.0 integrates very nicely with RSS feeds.
Firefox also allows you to customize how the browser looks by allowing you to download and install different themes.
The best feature, of Firefox, however, is that there are hundreds of extensions that you can use to customize Firefox to make it work the way the you want it to. I have several extensions that I use regularly. Because I have several favorite extensions, however, I will make those the subject of a later post.