A while ago, there was a thread about a display 'fuge -- all algae and pods. I love the look of a refugium, so I might do that if I were looking for something different. A species tank like an anenome tank can also look amazing -- there was an
RC TOTM that was all anenomes, and it looked wild.
On the other hand, I might also use it as a frag grow-out tank, or a QT.