Be careful with that DSB...I have had bad experiences with people who think that a DSB is the magical-cure-all for water quality issues. It isnt. And cleaning the substrate in closed systems will always be necessary in my mind.
That being said, I currently run a heavily stocked (blue hippo tang, midas blenny, 2x clarkii clown) 75g reef, and it is doing great (ammonia, nitrite, nitrate are all zero with bi-weekly h2o changes) and is housing mixed corals but mainly sps, with only a AquaC Remora skimmer. You can buy prefilter boxes for these that would also give you mechanical, biological, and chemical filtration, but I dont think you even need that. I would skip the HOB and get yourself a high quality skimmer, and an overflow box if you felt it necessary.