Es decir, que funcione el DVD, OGG / THEORA / AAC / MP3 / WMA / WMV/ DIVX / XVID / MPEG-1/2/4 / QuickTime support, Skype, Flash, RealPlayer, JAVA, etc.

Tres sencillos pasos:

1) sudo gedit /etc/apt/sources.list

Añadir la siguiente lista de servidores con repositorios:

deb http://us.archive.ubuntu.com/ubuntu/ dapper main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ dapper main restricted

# Ubuntu 'Universe' Repository
deb http://archive.ubuntu.com/ubuntu/ dapper universe main restricted multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ dapper universe main restricted multiverse

# Ubuntu 'Backports' Repository
deb http://us.archive.ubuntu.com/ubuntu/ dapper-backports main restricted universe multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ dapper-backports main restricted universe multiverse

# Ubuntu Security Updates
deb http://security.ubuntu.com/ubuntu dapper-security main restricted
deb-src http://security.ubuntu.com/ubuntu dapper-security main restricted
deb http://security.ubuntu.com/ubuntu dapper-security universe
deb-src http://security.ubuntu.com/ubuntu dapper-security universe

# PLF - Collection of Non-Free Proprietary Codecs & Applications
deb ftp://ftp.free.fr/pub/Distributions_Linux/plf/ubuntu/plf/ dapper free
non-free
deb-src ftp://ftp.free.fr/pub/Distributions_Linux/plf/ubuntu/plf/ dapper free non-free

# WINE - Windows API for Linux
deb http://wine.budgetdedicated.com/apt dapper main
deb-src http://wine.budgetdedicated.com/apt dapper main

# Skype - VoIP Software

deb http://download.skype.com/linux/repos/debian/ stable non-free

# Opera - Web Browser
deb http://deb.opera.com/opera/ etch non-free

2) sudo apt-get update
Para actualizar la base de datos de tu linux con los repositorios remotos.

3) sudo apt-get install totem-xine totem-xine-firefox-plugin libxine-extracodecs w32codecs libdvdcss2 flashplugin-nonfree sun-java5-plugin banshee streamtuner xmms skype msttcorefonts realplay f-spot
Instala los programas y librerías necesarios.

Leído en How-To: Get Full Multimedia Support and Playback Capabilities in Ubuntu Desktop Linux, a través de Menéame.