PCApex has a new PC Basics guide up covering the fundamentals of switches. Remember that this series of articles is aimed at the PC n00bs out there.
"Why bother installing a switch? The answer to that is really simple... control. A switch allows you to be in control of the state of activity of a component; whether that means a simple off or on state or something that will let you choose a setting among more than just two choices. For a device as simple as a cold cathode you may think, "Why even both with hooking up a switch when I can just let my lighting bling 24/7?" (or while the PC is on)."