Sometimes, its nice to know what your internet is doing. There is a little traffic monitor applet for the gnome panel called "netspeed" that shows how much traffic occurs on a network device (be it ethernet, wireless, or even dial-up). You can find it in the Ubuntu Software Center by searching on "netspeed".
After installation, you will need to right click on one of your panels (the top one or bottom one) and click "add to panel" to find the new app you just installed. In the list its labeled as "Network Monitor". Adding it and moving around to your fave place on the panel and thats it. Right clicking the app gives you more options and preferences.