SPCR

Here's pics my system. http://home.comcast.net/~pelikan/
I built a radiator out of 50' of 3/4" copper tubing and burried it in the ground outside. This chills the water to 10-15C. I run the chilled water through a small radiator in my case to chill the air. The case is sealed so the air inside recirculates via a 120mm fan at 7V. Sealing the case also prevented occasional condensation issues from the cold water.
Its very quiet with no holes in the case, I don't have to worry about dust anymore and the cold water makes for some nice overclocking.

Do you even need the heatercore? With a cooling loop that big, I would think that the external cooling of the water would alliviate the need for a heatercore, and thus, a fan. I have seen completly silent setups with people doing this, with the only noise coming from their HD.

The heatercore isn't to cool the water. I use it to cool the air in my case. My case is sealed so no air comes in or out. The air recirculates through the little heatercore.