If you are wanting a clean look, consider a single species tank. To me, nothing looks nicer than a healthy population of fish living in an environment made specifically for them. This is especially nice if you want to change your tank set up every few months.
Angels, discus, tin foil barbs, silver dollars, monos. All of these would work, and all can be traded in almost evenly for smaller fish after you've kept them for about six months.
For fish of this size, I would suggest an *almost* single species tank, with an appropriate smaller fish to grab the missed food.
-Shay