A personal quirk but I really don’t like having USB-mounted drives display in the Ubuntu launcher (Precise Pangolin). However, if you disable the display in the launcher, it can be a pain to unmount a USB drive. However, there is a handy ejecter app which will display an unmount utility in the system bar at the top.
So first install the compiz setttings manager which will allow you to disable the display of mounted drives in the launcher:
sudo apt-get install compizconfig-settings-manager
and then launch compizconfig, click on Desktop, then Ubuntu Unity Plugin to the right, then the Experimental tab and look for Show Devices and set that to Never.
Now install ejecter:
sudo apt-get install ejecter
Now whenever you have a usb drive mounted, you will see a little icon in the system tray that will allow you to eject it gracefully.