Ok, so I installed KDE on my Ubuntu 11.04 laptop. It worked ok, but I wanted to change back, and free up the space, so (having kept unity etc. installed), just rebooted into what GDM calls "Ubuntu". So far so good. 

I then wanted to rid myself of all KDE packages, so di sudo apt-get remove kde\* . I realise this was fairly silly. 

Now I've lost my sound applet in the system tray. It's more annoying than anything else, but I've got used to the play/pause functionality, so it'd be nice to get it back. Thanks in advance for whatever help you may be able to give!