A dedicated 15A circuit is definitely worthwhile if you can do it, possibly serving a quad receptacle (two regular "duplex" two-plug outlets side-by-side in the same box). You might even consider giving yourself two dedicated circuits, just to give you the resources to (for example) support a really big amp like the 770 plus a couple powered subs and a rear projection TV. Putting in a dedicated circuit at my old house to feed a quad outlet behind the entertainment center proved very useful for reducing hum in the system (which had previously been coming across the shared circuit from the refrigerator). In the new house, the circuit that serves the home theater isn't dedicated, but it's pretty lightly loaded aside from the home theater components.