Xubuntu has a nice way of showing network data flow in the panel; put the Network Monitor in the panel and choose the network interface.
I know that Gnome has a similar feature in its System Monitor http://www.thegeekstuff.com/2009/11/ubuntu-tips-graphical-monitoring-for-processes-memory-load-average-and-disk-usage/ - but is there an Xfce equivalent?
