For my one size fits all design, I chose the usb cable. With a socket that is becoming one of the more universal cable adaptors for technologies, the need for more cables is decreasing. The same cables can now be used to power computers, link computers to mp3 players, phones, printers, scanners, etc. Where many cables would be used otherwise, the USB cable can be used for all of these so individuals need less cables and less resources. 

For my eco-effective design i would use a solar water distiller. It is a cement structure which can fit along side a house which turns groundwater into distilled clean water using evaporation. For a small initial cost of building, it can supply anyone in a warm sun-lit climate with clean water without using any energy at all. It puts no dependency on anyone or resource except maybe rain.