Editing+Basics

Still Image Editors

 * When it comes to photo editing, **[|Adobe Photoshop]** is the program held up as the standard. It even has a watered down "Elements" version that you can purchase for much less than the full version. It's the one I use, but there are plenty of alternatives that are 100% free.
 * **[|GIMP]** is a free open source image editor that does most of the same things (and in some cases, more) that Photoshop does. It works very well on Windows, Macintosh, and Linux. Its power is also its weakness, however, as the large number of features it offers often confuses new users.
 * **[|ArtRage]** is a simpler program with fewer features than GIMP or Photoshop, but it still works remarkably well. There is a free "Starter" version available on their website, as well as a commercial product with more features.
 * Can't install any software? My Free Online Resources wiki lists a variety of websites that can be used to edit still images and even edit video.

Video Editors

 * Most computers nowadays come with either iMovie (Mac OS X) or MovieMaker (Windows) pre-installed. These programs will most likely meet all of your needs.
 * [|Adobe Premiere] (again, with an "Elements" version for the financially challenged) is a commercial product that is very powerful, including the ability to layer multiple videos on top of each other using green screen technology.
 * Can't install any software? My Free Online Resources wiki lists a variety of websites that can be used to edit still images and even edit video.