We recommended the following tools for creating artwork. They are all free software (free as in speech) and can be obtained by everyone at virtually no cost without any licensing-hassle. This simplifies sharing files and working together.
Promoting free software is one of the goals of Ubuntu and to do so, you should use free software yourself wherever you can.
Raster Image Editing
GIMP
GIMP is the GNU Image Manipulation Program. It's a full-featured raster graphics editor, roughly comparable to Adobe Photoshop.
Install GIMP
http://www.gimp.org
Imagemagick
A command line driven toolset, especially useful for batch editing, converting and adding text. Imagemagick let's you work at a plethora of depths including colourspaces and such. It can also render SVG and a very large file assortment. It is wonderful for creating, altering, and adjusting files.
Complete documentation is available at http://www.imagemagick.org
Install imagemagick
Icon Library
A python script which nicely displays an entire icon theme, including fall backs on different backgrounds with search function, etc.
https://launchpad.net/icon-library
Once the files are extracted from the archive, just launch icon-library.py.
pngcrush
A command-line utility that optimizes Portable Network Graphics (PNG).
http://pmt.sourceforge.net/pngcrush/
Install pngcrush
Wiki Scripts
Two useful scripts to deal with images for this wiki.
X11 Mouse Cursor Theme Creation
Feedback on how well these work or what the limitations are will be appreciated.
Gursor Maker – a cursor editor for X11 using GTK+.
XCursorGen – commandline tool to create an X cursor file from a collection of PNG images
Vector Graphics and Desktop Publishing
Inkscape
A Scalable Vector Graphics (SVG) editor. You can also use it to export raster type images.
http://www.inkscape.org
Install Inkscape
Synfig
A vector-based 2D animation package. Take a look at this YouTube video to get an idea of its capabilities.
http://synfig.org/
Install Synfig
Scribus
A desktop publishing program (DTP). Its awesome, and features the best PDF support this side of the free world.
http://www.scribus.net
Install Scribus
3D Graphics
Blender
A cross platform suite of tools for 3D modeling, animation and rendering.
http://www.blender.org/features-gallery/
Install Blender
Wings 3D
A specialist for subdivision modeling (think polygons).
http://www.wings3d.com/
Install Wings 3D
Video
PiTiVi
A movie editor for the Linux desktop. Included in Ubuntu 10.04.
OpenShot
A non-linear video editor.
http://www.openshotvideo.com/
Install OpenShot
Audio Routing, Recording and Editing
Audacity
Record and edit sounds.
http://audacity.sourceforge.net/
Install Audacity
Ardour
A multi-track audio recording and non-destructive editing application. For example, you can record an entire band, arrange the material, use effects and export a mix-down as single audio file.
Jack
JACK is system for handling real-time, low latency audio (and MIDI). It can connect a number of different applications to an audio device, as well as allowing them to share audio between themselves.
Combined Audio and MIDI Sequencers
MusE
Rosegarden
http://www.rosegardenmusic.com
Qtractor
http://qtractor.sourceforge.net
Audio Synthesis and Processing
Bristol-Synths
Bristol is synth emulation package for a diverse range of vintage synthesisers, electric pianos and organs. The application consists of a multithreaded audio synthesizer and a user interface called brighton.
http://sourceforge.net/projects/bristol/
Supercollider
SuperCollider is an environment and programming language for real time audio synthesis and algorithmic composition. It provides an interpreted object-oriented language which functions as a network client to a state of the art, realtime sound synthesis server.
http://supercollider.sourceforge.net/
Pure Data
Pd (aka Pure Data) is a real-time graphical programming environment for audio, video, and graphical processing. It is the third major branch of the family of patcher programming languages known as Max.
Composing music
MuseScore
MuseScore is WYSIWYG music notation software. You can create sheet music with your keyboard, your mouse or MIDI keyboard and see the result in the screen. MuseScore plays your music, print it, save to PDF or PNG for graphics purpose or MIDi/ogg/wav for audio.
Lilypond
LilyPond is an automated engraving system. It formats music beautifully and automatically, and has a friendly syntax for its input files.
Denemo
Denemo is a free software (GPL) music notation editor for GNU/Linux, Mac OSX and MS Windows that lets you rapidly enter notation for typesetting via the LilyPond music engraver. You can compose, transcribe, arrange, listen to the music and much more.
Nted
Nted is yet another open source music notation editor for GNU/Linux only. This, unlike others, features a unique interface, is able to import both midi and MusicXML, and is able to export to several formats, including PNG, SVG, PDF, and more.
http://vsr.informatik.tu-chemnitz.de/~jan/nted/nted.xhtml