By default, Ubuntu does not show Computer,home,network and Trash icon on the desktop in Ubuntu. Instead Ubuntu shows the Trash icon on the extreme right of the bottom panel. Also having the Trash icon on the desktop in Ubuntu is a good option, because it becomes easier to drag - drop files onto the Trash icon.
This document describes how to set up the light-weight Conky system monitor on Ubuntu 7.04. Conky is a desktop widget that is able to display most diverse information like CPU temperature, current used network-bandwith or anything you want. You can customize the whole layout including colors and fonts.