The environmental aspects of your aqurium should definatley be in consideration. The vast majority of our oceans and especially coral reefs are extremely threatened by among other things, ovcer fishing and the pet trade. There are plenty of good ways to go about having a great aqurium without damaging these fragile ecosystems.
For info on coral reefs:
http://www.coralreefalliance.org/
And more on conservation friendly aquariums here:
http://www.aquariumcouncil.org/