Blender (http://blender.org) is the open source software for 3D modeling, animation, rendering, post-production, interactive creation and playback.
Blender is an industry standard, featuring broad functionality and extremely intuitive interface, completely sufficient for thorough production studio set up.
Cinelerra (http://heroinewarrior.com) does 3 main things: capturing, compositing and editing audio and video with sample level accuracy.
It's a seamless integration of audio, video and still photos.
GIMP (http://gimp.org) is the GNU Image Manipulation Program. It is a freely distributed piece of software for tasks such as photo retouching, image composition and image authoring.
Ardour (http://ardour.org) Ardour is a digital audio workstation. You can use it to record, edit and mix multi-track audio as well as mix video soundtracks and experiment with new ideas about music and sound.