Code Editors
These are a few of my favorite code editors. I recommend trying as many as you can, as personal preferences play a big part in choosing an editor.

Atom
Open source code editor developed by Github. Highly customizable and fantastic built-in integration with Github.

Brackets
Lightweight open source code editor that's built on HTML, CSS, and JavaScript. Highly extensible and fast, with a Live Preview in Chrome built in.

Dreamweaver
Robust web development tool from Adobe. Part of the Creative Cloud subscription service, features a powerful code editor.

Notepad++
Free, open source code editor for the Windows platform. Not as full-featured as some editors, but has a large community of users.

Sublime Text
Commercial, cross-browser code editor. A favorite of many web developers. Features a simple and clean user interface.
Content Management Systems
This is by no means a comprehensive list of available Content Management Systems, but it should give you enough variety to explore as you take a closer look at how they work.

Drupal
Full featured open source CMS platform. Has a huge development community and powers many of the web's largest and most popular sites.

ModX
Powerful open source CMS. Gives a little more control over the design to the designer, as it's not as constrained by templates as others.

Movable Type
Commercial CMS favored by many creative agencies and designers. Movable Type is not cheap, but it's stability and features have made it a favorite among the design community.

Perch
Small commercial CMS that is designed for creating editable regions that clients can edit and maintain. A great alternative to the larger, more complex options.

Wordpress
What started out as blogging software has evolved into the biggest CMS on the market. Huge development community.
Graphics Software
Programs for creating web graphics and other visual assets.

Adobe Creative Cloud
Industry-standard graphics design suite featuring tools such as Photoshop and Illustrator.

Adobe Fireworks
Although Adobe has removed Fireworks from the Creative Cloud and has no plans to continue developing it, this web-centric graphics software remains popular with many web designers.

Gimp
Open source graphics editing software. Cam be tricky to set up, but its gaining popularity among designers.
Web Frameworks
Web frameworks are software frameworks that are designed to support the development of dynamic websites, web applications and web services. The framework aims to alleviate the overhead asscoiated with common activities performed in Web development. Some of the most popular frameworks for developing sites

Bootstrap
Immensely popular HTML,CSS, and JavaScript framework originally developed by Twitter. Emphasis on responsive design and mobile development.

Foundation
Feature-rich framework from Zurb that controls layout, behavior, and more. Designed to be responsive and provide responsive solutions for content and images.

HTML5 Boilerplate
Not exactly a framework, HTML5 Boilerplate is the most popular front-end template. It's designed to give projects a starting point based off of best practices for HTML5.

Skeleton
Lightweight, minimal framework that focuses on layout and project foundations instead of providing a full UI solution.

YAML
YAML stands for 'Yet Another Multi Column Layout'. Modular framework that lets you control as little, or as much of your project through it as you wish.
JavaScript Libraries
A JavaScript library is a library of pre-written JavaScript which allows for easier development of JavaScript-based applications, especially for AJAX and other web-centric technologies. The following is a list of an introductory collection of popular JavaScript Libraries.

Angular
Application development framework designed for creating dynamic sites. It uses HTML as a template and then allows you to extend HTML to components that you define.

Ember
Similar to Angular. Templating framework designed to make building applications faster and easier.

jQuery
Feature rich JavaScript library designed to make writing JavaScript easier and more powerful. If you're new to JavaScript or JavaScript libraries, start here.