I have a 15G sump on my 29G. I agree, not necessary but it makes filtration a lot easier and cleaner. I don't like unnecessary stuff in my tank like pumps for skimmers/reactors and heaters.
I have decided to use a commercial overflow box with w 10 gallon tank. What do you all think about the Eshopps overflow boxes??? I'm thinking the 300 gph one... what do you think???