I recently installed Ubuntu on my computer and i need some help to get started, since i'm only using a small amount of my hdd for linux would i like to uninstall some of the package that is installed as standard but i'm a little unsure how i should do this and what packages to remove.

A other problem is what music player i should use to play streaming music from radio stations, think most play mms music so i'm in need for a player that can play it or a codecs, i think rhythmbox can handle it but i need a codecs for it and i have no clue what package. I thought rhythmbox since it's allready installed or is it better to get a other one and uninstall rhythmbox and all the other music players?

EDIT:
I'm unsure why DOM inspector in firefox isn't in the ubuntu version, did check mozilla.org and it did say that all firefox versions have it but i can't find it or where to get a addon for it.

This is a good place to start: https://help.ubuntu.com/

To play streaming music you need to add the win32codec package. The site above will help you to add the required repositories. It also deals with adding and removing packages.

This site has some good information on installing various multimedia codecs: https://wiki.ubuntu.com/RestrictedFormats

There are also links to various multimedia programs.