I've got a 100 gallon tank that's recessed into the wall of my living room. Originally, it was a saltwater tank with live rock, coral, and fish. I had the whole setup including metal halide lights, chiller, cooling fans, wet/dry sump filter, basically everything that's required for a reef tank. It ran good for a few years, but then the chemical balance got out of whack with the water, and I had an infestation of hair algae that I could never get back under control. Corals started dying off, so, I decided to go the easy route and go to freshwater.
Now I have several Leporinus in the tank, some of them are 8" long. Very easy to maintain, only have to add well water, no more of that expensive reverse osmosis water, no more having to buy expensive salt to mix it, not to mention all the other stuff like calcium and the other minerals a reef tank requires.
Reef tanks are nice, but if you set one up, be prepared to deal with a full-time job of maintaining it.