Photoshop is a must have application for any video editor.  Photoshop CS 3 now includes a video timeline with the ability to do basic video editing.  Don't get me wrong, you'll still need your favorite non linear editing system such as Final Cut Pro or Avid to the majority of your video editing.

However, this means you can use Photoshop's extensive array of tools to perform color correction, and rotoscoping.  You can also use Photoshop's filter gallery to apply filters directly to a video file.

Other features of Photoshop CS3 extended include the ability to import 3D models.