I'd go talk to the folks at Aquarium off Papermill. They seem to know their stuff and really have a great selection of both fish and invertibrates for the tank. I've heard it's a little bit of a chore but have always wanted to set up a saltwater tank. My closest accomplishment is a 90-100 gallon tank of African Cichlids at the office. I used pool filter sand, locally-collected river rock, live plants, and driftwood. I'll try to get you a picture sometime if you're interested. Cichlids are about as interesting as you can get and still stick to freshwater. They are a little on the tempermental side and have certain water demands that require a little more work than your basic tetras, swords, etc.