All the tools you need to make art digitally are available as Free Software projects. These aren’t toys, they are serious tools used in production on real projects.
Blender is an excellent 3D modelling, animation and game-making application: http://www.blender.org/
Renderman is the tool that’s used for rendering movie effects and computer animation, free implementations are available: http://www.renderman.org/RMR/OtherLinks/index.html#Renderers
For video editing there’s Kino: http://kino.schirmacher.de/
For frame editing there’s CinePaint (formerly Film Gimp), developed and used by Hollywood effects houses: http://www.cinepaint.org/
For photo and image editing there’s Gimp: http://www.gimp.org/
For vector illustration there’s Inkscape: http://www.inkscape.org.
And there will eventaully be minara :-) : http://minara.sourceforge.net/
For fonts (typefaces) there’s Fontforge: http://fontforge.sourceforge.net/
For desktop publishing there’s Scribus: http://www.scribus.net/
Other Free Software media resources, including sound, sampling and sequencing (which are outside my area of expertise): http://lib.fo.am/cgi-bin/view/Libarynth/FreeMediaTools