Arkman,
I agree that aquacultured is very nice, but I have to disagree with you on your rock theory. MOST (and I say that with some exclusion) of the rock harvested for the hobby can and is replaced through time. For example, Fiji rock appears to be nothing more that a conglomerate of things, including dead coral structure. I'm not certain of the cementation process, however due to its very porous nature, it appears to be easily brought together. Reef build up in certain areas continues to occur, while in other areas it does not. Whether or not the build up in certain areas occurs faster than the hobby that purchases it is a different matter. I believe that the seemingly faster (in geolical terms) rate of conglomeration in the reef rock known as "Fiji" is probably the reason it is the most prevalent live rock on the market. If someone else has better or contradicting info, I'd be interested.