Below are the Firefox plugins I generally use and recommend to people:

• AutoCopy
• ColorfulTabs
• Download Statusbar
• DownThemAll!
• external IP
• Firefox Showcase
• Flagfox
• Xmarks
• Groowe Search Toolbar
• LinkedIn Companion
• New Tab Homepage
• Session Manager
• ShowIP
• Speed Dial
• Tab Mix Plus
• Video DownloadHelper
• WebMail Notifier

Always find a good team that you can work with for coverting PSD files and indesign files to html, css and javascript, here is a good one that I know of call xhtmlized.

Site Design:

• zurb.com, a bit more expensive but they’ve worked with tons of startups.
• electricpulp

This is a great place to find stock photos for you sites

• istockphoto.com

MS Windows editors:

• Notepad++, some tips can be found here.

Online resources:

• gomockingbird, one of the best wireframe tools ever.
• CSS Cleanup Tool
• HTML Cleanup Tool
• Blueprint CSS Framework (e.g. Example)

Create a favicon.ico

Firefox development plugins:

• Add N Edit Cookies
• DNSStuff Toolbar
• Netcraft Toolbar
• EditCSS
• Firebug
• Html Validator
• LinkChecker
• Server Switcher
• Total Validator
• View Cookies
• Web Developer
• YSlow
• IE Tab
• Page Speed from Google
• HttpFox, to view GET and POST data from HTTP requests
• Fiddler, to view GET and POST data from HTTP requests

Google Chrome plugins:

• Web Developer

SEO Tools:

• Free SEO report
• The Top 15 Free SEO Tools

Certificate Verification:

• Validate Your Verification