What software can be used for traffic monitoring in Ubuntu Linux?

In this case, I was using Ubuntu  Linux 10.10. And found the following applications in the archives:

• iftop. Something like “top”, but for the console, and for one network interface.
• trafshow. Not unlike iftop.
• vnstat. Needs some configuration of a “database” before it works. It will also keep a log of daily traffic values.