Output

Printer - a device that produces a permanent human-readable text of graphic document.
Speakers - typically a pair of devices (2 channels) which convert electrical signals into audio.
Headphones - for a single user hearing the audio.
Monitor - an electronic visual display with textual and graphical information from the computer.
CRT - (Cathode Ray Tube) as of 2010, it is a mostly obsolete technology replaced by LCD panels.
LCD - (Liquid Crystal Display) as of 2010, it is the primary visual display for personal computers.