If your case doesn't have a spot for an extra 80mm case fan on the rear, you really owe it to yourself to get one that does. You could pick up an Enlight 7237 without a power supply, it comes with a quality ball-bearing fan and is not very expensive, . Here is the
7237 without power supply at Onvia for $46 shipped. The 7237 has four exposed 5.25" bays, which scores points with me. If three 5.25" are enough, you might consider the Antec SX830, which comes with two fans and a power supply.
If you are planning to keep your case and it doesn't have a spot for an auxiliary 80mm rear fan, you might put a high-output 80mm fan in your power supply to increase its exhaust capacity. But when you look at the cost, that $46 7237+fan deal is hard to beat. You could also pick up a second 80mm ball-bearing fan from them for the front:
80mm fan at Onvia and they have the slot fan too:
Slot fan If you want a hard-drive cooler kit, I am sure they carry them also. Keep in mind the balance of intake and exhaust... you don't want all the exhaust fans fighting eachother. If you plan on having two 80mm's in the rear and a slot fan too, you want to give the air a way in the front, either with a hard-drive cooler kit or maybe just drilling a grid of 1/4" holes in the 5.25" bay blanks. Good idea to drill the vent holes in the 7237's bezel to 1/4" as well... they are pretty small.
edit: looks like Onvia no longer has free shipping on the cases It's still under $10 to ship it to Washington via Ground shipping.