Mozilla has this to say about its Firefox product:
The award-winning Web browser is better than ever. Browse the Web with confidence - Firefox protects you from viruses, spyware and pop-ups. Enjoy improvements to performance, ease of use and privacy. It's easy to import your favorites and settings and get started. Download Firefox now and get the most out of the Web.
I like firefox for avoiding spyware. I also use it for development and troubleshooting web pages. It has many developer plugins available that are very handy for debugging, and for Search optimization. You can port over all of your favorites from IE.
I first encountered Firefox at home when I had a PC get very infected with Spyware. I needed another working browser to read the fixit steps on the various spyware forums. I liked the application. It was able to stay clean while I fought and fought to get my IE working properly. If I wasn't a web developer, I would have just canned IE altogether. But I still need to be able to support ID, so now I run both. My only complaint with Firefox is that it opens very, very slowly.
If Internet Explorer hadn't caused me countless hours of grief I wouldn't bother to endorse another browser, but I truly feel that Firefox has alot to offer and is worth considering switching to for the average internet user.