There are many peripheral components that are not necessary to the system itself but may be necessary to specific induvidual. Components such as speakers, scanners, and digital cameras are common and affordable. Little else would be useful to a home user, so they will not be discussed. Speakers usually come with the systems, but better quality speakers can be had for a price. It is probably best to avoid spending money here because better speakers are pretty unnecessary for a home computer system.
Scanners are an input device that are becoming more widespread.
They can be used to transfer photos and pictures into the computer. They are not really necessary, but they do serve a neat purpose. I think in the not too distant future they will be a part of a majority of home computer systems. Currently, they are not too expensive, so I think they are worth the buy. Digital cameras, like scanners, can be used to transfer photos onto a computer.