x2cm590
Got one myself. 3x120mm or 140mm fans can be fitted in front quite easily. Before I had that case the hard-drive were sitting around 50 degrees with a single 120mm fan blowing air on the drives, in the CM590, 36 degrees (that is on 6x2 TB Seagate low power drives, values retrieved using S.M.A.R.T). All the PC hardware and PSU also run much cooler now because everything is very well spaced out.
To use the CM590 will require 3.5" -> 5.25" drive bay converters however (can fit up to 9 hard-drives using them).
Most other cases don't have fans blowing on the hard-drives, which is good, if you like your drives to run hot or have good airflow in the room.