What Internet bandwidth speed tools are available?

I use nethogs. Console program. Works great.

sudo apt-get install nethogs

gkrellm and conky are useful monitoring tools for gnome that will allow you to have a visual of your network bandwidth behavior. Both them are not limited to the monitoring the network activity. Screenshots here:

gkrellm

conky

more conky's screenshots available at: http://conky.sourceforge.net/screenshots.html

speedtest.net is awesome, no need for an app...

You can use Netspeed monitor applet. At 1st, install it from software center, simple "netspeed monitor" will give you the result, install the package. Now if you are using GNOME, right click on panel, select add to panel and then select netspeed monitor. You can see the incoming and outgoing speed on the panel all time