AutoCopy

AutoCopy instructs Firefox to copy text when it’s highlighted. Very helpful when copying content from a customer’s old site into their new one.

ColorZilla

ColorZilla lets me place my cursor over anything on the page and it gives me the hex color of the pixel. It’s a huge time saver as it allows me the ability to avoid doing a print-screen, opening Photoshop, and using the Photoshop color dropper to get the color.

Firebug

Firebug is an absolute must for my Ajax / Javascript debugging. I couldn’t get by without it.

HTML Validator

HTML Validator just validates how great my code is.

Link Alert

Link Alert changes my cursor when I hover over a link. The cursor changes to a visual representation of what I’m about to click on. It’s great for me because it tells me if the link is to a javascript file, text file, or mp3 file. I love it. It also tells me if clicking on a link triggers a javascript event.

MeasureIt

MeasureIt gives me a ruler to mention object dimensions. This tool gives me a broad idea over how much space an object is taking up or how much space I have left to work with on my page.

Server Spy

Server Spy is dominant because I can instantly tell what type of server the current website is on. A must when trying to quote a new project.

Web Developer Toolbar

The WDT is as important to me as Firebug. WDT gives me a ton of control and information about the page I’m developing. Again, this is a must.