[pogodzib]

A sump is not necessary, but is always a very nice addition to any tank - adds water volume, hides equipment, place for macro algae, etc... Unless you want to maintain the power filters or wet/dry filter often, I would ditch both and get a good skimmer. Between the skimmer and your live rock, you don't need any other filtration, and it would be cheaper in the long run because you don't need to keep replacing the filter all the time.