Firebug as a tool for Web Developer

There are lot of style and way on how to enhance the design of your web. There are lot of tools which allows you to copy and enhance the existing design in the internet. One example of them is the Firebug. Firebug integrates with Firefox to put a wealth of development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page...
Anyway, I'm wondering, I came from an article mentioning various addons like this for web developers, that do on-the-fly CSS rendering and such, and wonder, do you use this in conjunction with other addons like that, or do you generally only need one? Is this the best one? I see good things about Webdeveloper as it has a resolution resizer also, but I see the Firebug name a lot more.

Firebug can do the following.

• Inspect HTML and modify style and layout in real-time
• Use the most advanced JavaScript debugger available for any browser
• Accurately analyze network usage and performance
• Extend Firebug and add features to make Firebug even more powerful
• Get the information you need to get it done with Firebug.

For more information about the Firebug tutorials:

http://getfirebug.com/whatisfirebug