These are the tools that I have used most frequently in my online learning projects.
Canvas - An up-and-coming solution in the LMS space
Android SDK - Create apps for your favorite Android devices
Drupal - Drupal is an awesome and extermely flexible CMS
JavaScript - Great for client-side scripting
jQuery - Super powerful JavaScript library
PHP - Easy to use and powerful, PHP is a great server-side language
Adobe Creative Suite - The industry standard for creative solutions
HTML5 - Nothing like semantic markup to make your websites sing
MySQL - Excellent database platform for web apps
Unity3D - Beautfiul game development platform for web and mobile devices
Blender - Awesome open-source 3D modeling tool
Elgg - Open-source social networking platform
YouTube - Free video sharing