Best cooling approach for A8N-SLI wth dual POV 7800 SLI cards

I am considering buying a better cooling system for my PC.
I have my hw stacked up inside a Coolermaster CM Stacker 810.
I run a A8N SLI Premium and two Point Of View 7800 SLI cards.
There are 8 HDDs in there also, so naturally the system is not the coldest
place in the room.
The CPU temp runs at 45C most of the time, which I think is a bit on the high
side.
I have mounted the Cross Flow Fan and will mount the Susurro CPU fan (16dB
noise level) this week, but I still want to cool down the system a bit more, as
well as keeping down the noise level.

Does anybody here have any experience running a watercooled system like this?
Or maybe have some other recommendations about how to get to the coldest
possible and most silent state without switching the thing off :)

tia
Olav


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