A software package a day: Firefox as development tool
Developing web based software can be a challenge, but it can be a lot easier with the right tools. With Firefox and a few plug-ins you have some excellent tools for a grand total price of zero. Over time I accumulated quite a few plug-ins that I feel make a web developer more productive. Here is my current inventory specifically for web development: Fiddler, Firebug, HTML Validator and the Web Developer. Beyond these I use Adblock Plus, Delicious Bookmarks, DownThemAll!, Greasemonkey, NoScript and Prism for various non-development tasks. I am amazed that Firefox remains stable with all these plug-ins running, but it works great.
With these tools at my disposal I can tackle virtually any web page challenge easily… and all for free.