I am one of the biggest Firefox fans out there. I could give you a whole pitch about why it's a better browser for everyone, but I will focus on web development. For standards based web development Firefox is an indispensable tool. Successful web production requires a lot of tweaking that in most other cases would require a lot of round trips between the browser, a graphics program and your HTML/CSS editor. Firefox comes with a broad selection of extensions. Some of these extensions are extremely useful for testing and validating your web page.