Resources
This is a collection of useful applications and references I have found very helpful during my work.
General
Firebug
Firebug integrates with Firefox to put a wealth of web development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.
Modify Headers
This firefox plugin allows you to add, remove or modify headers. This is very handy when developing mobile websites, because it allows you to fake your phone number or other IDs during testing.
LiveHTTPHeaders
Allows you to look at web page headers. Once again, very handy for mobile development.
WinAmp
Despite it being bought out by AOL, older versions of WinAmp are still my favourite choice for playing music whilst I work. I'm currently using version 5.35, which you can get from oldversion.com.
Linux
vim
vim is a text editor for Linux that takes a bit of time to learn but is very simple and powerful when used properly. It has the advantage that it can run in a shell, so can be used to edit text on remote machines.
grep
grep has saved me so much time when it comes to finding where functions are declared or where a specific comment is in 100+ code files. The best way I use it is to cd /directory/of/files and type grep -in 'text to find' -R ..
Windows
Notepad2
Despite not being updated for a while, Notepad2 is my Windows text editor of choice. It's Notepad on steriods. I mainly use it for syntax highlighting, but it's got a good find and replace and other features you'll find over time.