Just put up this list to share with others in the team so thought I might as well post it here since it could be useful to folks starting out in web development. Do feel free to add on to the list if there’s something useful for us to use.
Hard Core Editing (i.e. know your markup)
Web Developer Toolbar https://addons.mozilla.org/en-US/firefox/addon/60
User Agent Switcher https://addons.mozilla.org/en-US/firefox/addon/59
IE 6 and 7 Internet Explorer Toolbar http://www.microsoft.com/downloadS/details.aspx?familyid=E59C3964-672D-4511-BB3E-2D5E1DB91038&displaylang=en
IE 8 has built-in developer toolbar
Adobe Dreamweaver CS4 (it really does its job well, have tried hard to replace it without much success)
Adobe Fireworks CS4 (started using Fireworks since Macromedia days and its my favorite program when a mock or design is needed)
Balsamiq http://www.balsamiq.com/ (Just started using this recently to improve my pen n paper process and its working out nicely)
Hope this helps you in your daily work. Happy coding!