Linux Magazine had a feature written by Charly Kühnast describing the application "nmon".
This app was a simple "sudo apt-get install nmon" away and was in my Ubuntu 10.04 repos with no further setting changes required. The application does need to be run in a terminal. It does not require root permissions and has a great many monitors that are available for viewing in both a real-time and a collection mode depending on how geek your statistic and performance needs are.
I have a screen shot here of the application running in a tall 1/2 wide screen with just a few (not all) of the monitors activated.
In my set up I have activated all except memory and processes and run the "htop" command in the a terminal adjacent which then shows almost all possible performance real-time data available in one manageable and comprehensible screen.
Enjoy this app and add it to your list of favorites to use while embracing the command line.
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