What is meant by an All-In-One computer? Simply it means that the parts of the computer; the hard disk, DVD/CD drive, processor, and memory are placed behind the display screen resulting in one compact package. In addition, many All-In-One computers have touch-screen capability that could potentially help to speed data entry with the proper programming.
But why else am I writing about this? It is because the All-In-One computer format is also a green machine in that it uses much less electrical power than the standard desktop computer. The All-In-Ones I looked at used a 65 watt or lower power supply. In contrast, a survey of currently available desktop PCs showed they used from a low of 220, to a high of 450 watts of power each. Multiply this by 25, 50, or 100 computers this turns into a significant amount of power and heat.
If you are interested in more detailed information; I found the following review article for this style of machine from last fall on the Computer Shopper website. It provides a quick overview of the All-In-One machines that were available at the time.