System Load Indicator (or Indicator-Multiload) is, as its name says, an appindicator that exposes your system load (CPU and Memory usage, Download/Upload speeds, etc) by simply clicking it (starting with this 0.2 release).
This new version brings a menu filled with system values to previously charts-only System Load Indicator.
Launch System Load Indicator 0.2 via the Dash ("Autostart" is enabled by default, but you need to launch it on its first time usage).
If you want to stop its start after every login, click on System Load Indicator-->Preferences-->uncheck "Autostart"
How do we install System Load Indicator 0.2?
Add the following PPA (Natty, Oneiric)
sudo add-apt-repository ppa:indicator-multiload/stable-daily
sudo apt-get update
sudo apt-get install indicator-multiload