Useful System Statistics Linux/Ubuntu Command Line Program - Dstat

Sample dstat output from my Ubuntu desktop

I was looking for for a Ubuntu command line program to monitor my desktop's network speed.  I found this ubuntuforums.org page that mention dstat.  It's easy to install
sudo apt-get install dstat
It not only monitor your network card speed, but also monitor cpu, disk i/o and many more.  See the dstat official page for more information.

Btw, here's the dstat man page (manual page)