Electronics and computers
Mouse and keyboard: Indispensable on the computer
The computer industry has long been working on input methods that are supposed to make mouse and keyboard superfluous: From voice input to gesture control to data gloves, pretty much every technology has been (and still is) tested for its suitability for everyday use. Apart from touch screens, however, none of this has yet caught on, and so mice and keyboards are still as much a part of every PC as its power cable.
Apart from minor constructional and ergonomic differences, the question of which product is the right one is mostly limited to how the input device is connected to the PC: With cable - or wirelessly, i.e. via radio (usually BlueTooth via USB dongle). The rest is a question of build quality and personal taste!