Antec Three Hundred Illusion Black Steel ATX Mid Tower Computer Case will cost about $70 with shipping but is a very good case and worth the price. Think you would be very satisfied with the case and it's cooling capabilities.
I was looking at the antec 900 case since it was on sale however some people had said on the internet that the 8800 series only just fits. Thats like my case now. it just fits pushed up against the hd.
Thats a bit of what I meant. $60 can get you a new 500GB drive from newegg. If you have some 160 or 250GB drives as part of those six, you can copy them over to the new drive. Then your only running 5. (or less if you have a lot of older 80/120GB drives.) This means less power use, less heat, etc.