Arctic Cooling Accelero S1 Rev. 2, with a set of turbo fans if like me you are paranoid about heat issues. I can hear the HDDs over the top of the fan noise. I spent a couple of days looking into the best option, and pretty much every place I looked was saying these are about the best. I even asked on here.http://www.arctic-cooling.com/vga2.php?idx=147
I'm running a Sapphire 4870, and it's sits cool and quiet. I tried the fan "fix", and it was still too noisy for my liking.
Temps show in graph below. I've just had an hour of STALKER (Stopped about 5 mins back), so it's had a couple of mins to cool, but it's running 7*C cooler than on the stock HSF at idle even now.