My 15 gallon rimless:

It's an SPS dominated tank mixed with some LPS and softies (ric, zoa, and gorg). There's also a resident derasa clam, a clownfish, a royal gramma and assorted snails. It's lit by a 150w Phoenix 14,000K. The overflow in the corner drains to a small sump containing a protein skimmer, a media reactor with carbon, a heater, and an ATO system.
Though the actual tank (24 x 12 x 12) is new, everything else was simply transferred over from an established 10 gallon tank that I had before. (The previous 10 gallon tank had been running since February.)
See the thread link in my sig for more details.