http://www.purple-planet.com/

http://www.musopen.com/

http://www.incompetech.com/m/c/royalty-free/

http://www-plan.cs.colorado.edu/henkel/fso/index-en.html

http://en.wikipedia.org/wiki/Wikipedia:Sound/list

http://www.atom.com/creators/creators_kit/

http://www.soundclick.com (Search by License type: Creative Commons)

http://ccmixter.org/ (some are non-commercial only)

http://opsound.org/ (Some are non-commercial only)

Arhive.org Open Source (Search for audio with Creative Commons license)

Archive.org Search

Sound FX:

http://www.soundsnap.com/

http://www.freesound.org/

Images:

http://www.sxc.hu/index.html

Cheap Music:

http://www.freeplaymusic.com/

http://www.beatpick.com/