Normally the first thing I do with a new ubuntu install is a "sudo apt-get install ubuntu-restricted-extras" which installs a lot of media codecs (dvd and so forth) as well as a lot of gstreamer packages for audio on top of other things. This will also install java6 jre, some ms fonts, some flash plugins and other packages. This is a pretty good package to install before you actually start using the os as a desktop.