There's some great tools and services available out there to make web development easy, below is a list of the ones I use on a day-to-day basis. I'll be uploading some tools and templates of my own later this week.

Adobe AIR

• Pixus
• Pixel Perfect
• Adobe Kuler
• Colour Picker
• Snippely
• Boks
• SQLlite Sorcerer
• EM Calculator

Firefox Plugins

• Web Developers Toolbar
• Live HTTP Headers
• Firebug
• IE Tab
• Font Finder
• Hackbar
• ColorZilla
• LoremTools
• XPath Checker
• SQLite Manager
• XML Developer Toolbar
• User Agent Switcher
• SQL Injection
• Gridfox
• Tamper Data
• 960 Gridder, Bookmarklet

All of the firefox plugins are available as firefox collections.

• Database Toolbox
• Web Development Tools
• Security Tools

Linux Utilities

• IE 4 Linux

Dreamweaver Plugins

• Ruby Weaver - Adds rails support to Dreamweaver
• Drupal API extension for Dreamweaver