I like the cooling arrangement on the Antec 300 series cases. These are large cheap sturdy cases with lots of drive bays.  There are exhaust fan openings on the top and the upper rear of the back panel, and of course whatever power supply you add will exhaust its cooling air out the back as well.  There's a side panel opening for a fan that will direct outside air at the processor and graphics card area, and you can add two fans at the front to push outside air through the drive bays.  I stack my drives with open air in between them for better cooling.  All pretty standard nowadays, but they arrange it well.  Each side opens with a latch, or you can screw it shut when you are done fiddling.  Both sides of the drive mount screws are accessible, not hidden below the mother board.  Antec sells fans that mount on rubber bushings and are held in place by rubber bands.  They have a hi/low switch on the power cable, and with my setup I can run the 5 fans on the nearly inaudible low setting for high volume/low velocity cooling.  Beats our previous Dell which had one fan for everything and tried to keep the processor cool with creative ducting.  That fan was screaming when we ran Photoshop.