Though I'm sure others feel differently, I consider an SPL meter and a setup disc, absolute essentials. Many think "Shoot! Why should I invest the money if I'm only going to use it once." If you move your speakers, even a little, or change or replace certain pieces of equipment, you should recalibrate. I just added a Denon DVD2910, and needed the meter to calibrate the 5.1 analog outputs. Plus, the discs help you calibrate your TV or projector for optimum usage. I just removed a BFD from the chain to my subwoofer, and I've got to recalibrate today. Both items come in real handy.
