Before You Buy A Home Theater Receiver – AV Receiver – Surround Sound Receiver
About.com has another great article covering the basic technology of receivers. They cover everything from the "More Watts is Better Myth" to defining decibels. This is a must read before you start out shopping for your next receiver.
From the article:
Don't base your buying decisions from a single specification, such as a Watts-Per-Channel rating. A single spec, taken out of context with other factors, does not give an accurate picture of the receiver's true capabilities. There are other factors to take into consideration, such as, sound quality, ease of use, and flexible connectivity with other components. Never buy a receiver without giving a listen for yourself. Make sure the dealer allows a 30-day return/exchange if you are not happy.