Another nice thing about a sump / fuge is that it can be a good place to put a remote deep sand bed (rdsb). Anthony Calfo has a great thread about those over on ReefCentral.
You can split the DSB up into a few plastic containers, and switch them out whenever you feel the need DSB's do a fantastic job of clearing the water of phosphates and nitrates, in my experience, but this way you get the benefits of a dsb along with the substrate of your choice in the display, and easy maintenance as well. much cheaper than running phosban and other reactors to help clean the water.