Watt's in a Name?

Suggestion from a fellow tech, "Please tell us about wattage in power supplies." My immediate response is buy the largest power supply made by a a good manufacturer like Antec. There's more to it than that though. Here it's entirely possible for me to muck through an analogy concerning the properties of electricity and their similarity to the flow of water through plumbing, but others have done this before me. Let's leave that to the experts.

Try JourneySystems. This is a power supply calculator. It doesn't list the latest greatest devices available, but is still a pretty good tool. How Stuff Works has a list of the average power used by each device in a PC. If you want a bit more detail try Direction.org. For a VERY detailed explanation of wattage try this "definition" at Wikipedia. The water flow analogy? Again, take a look at How Stuff Works.

watt--
A unit of power. A watt is a measure of how much power a device uses when turned on, or how much power a device can supply. A watt is a watt. There is no such thing as "watts per hour", or "watts per day". If a something uses 120 watts, that measure of 120 watts is the voltage times the amps. If it pulls 10 amps at 12 volts, or 1 amp at 120 volts, either situation is still 120 watts. One watt is equal to one ampere of current under the pressure of one volt; therefore, it is obvious to the most casual observer that YOUR computer needs at least a 150 watt power supply! Right. (What?) For those that want to know, the formula for power is P=IxE. In corporate America, it is become the President or it is "Who has the fastest computer?" and "Who can I step on next?".
watthour--
An amount of energy used to continuously supply power to an electric circuit for one hour. For example, a lamp rated at 100 watts that was on for 3 hours would consume 300 watts of power.
-CSGNetwork