Some of those coolers look pretty expensive, not to mention HEAVY, and maybe too noisy
I want to reduce fan noise!
A mates bought a Zalman CNPS9500:
http://www.scan.co.uk/Products/Produ...oductID=256319
he asked me to fit it for him and it's HUGE and HEAVY!!! It's heavier than the weight recommended for the socket, that's a concern! It has a fan controller and it's quiet, but it can get noisy if you want to get the temps down more.
The recommended weight for socket AM2 is 450g, the Zalman weighs 530g and Zing, that bloody Noctua NH-U12F weighs
790g 
I've just built this system and it's gotta last a few years, don't want some fancy cooler doing some unseen damage due to it's weight!
My PSU doesn't have a fan underneath so all hot air must be exhausted at the rear, that's why I have 3 x 80mm fans exhausting air. The CPU Fan has a 4 pin header as AM2 supports PWM fan control, so I think that's why the CPU Fan speed gets louder as the temp goes up.
And as I understand the ducting, it's best to have a gap between the end of the duct and CPU heatsink so the cooler air has a clear path down and air won't get obstructed if it hits the heatsink directly if the duct is touching it.
So I have 2 scenarios: Better HSF or Ducting!
Ducting sounds plausible due to having a bigger fan than on the CPU pushing more CFM's down the duct to the heatsink, so the cooler outside air hitting the heatsink will also mean less heat coming off the heatsink and being blown into the case. The combination of the 80mm fans exhausting and 120mm fans directing the hot air to the rear of the case should keep it cool. I also have an 80mm intake fan at the front blowing cool air onto the 120mm fan under the HDD bay, so in theory (famous last words) it sounds 'cool'
On the other hand, a f00king big heatsink and fan the size of a breeze block hanging off you CPU socket looks a bit worrying! Yes, some have a bracket on the back of the motherboard they clamp onto, but it's still heavy! They probabaly do work but some can't have the fan moved so air is either blown straight down or sideways, something that needs to be considered when orienting fans.
In all honesty, I've spent way too much already to splash out on a £30-£40 HSF, hence the ducting query, i'm not made of money unfortunately so I just can't afford that option yet!
If people still feel ducting is a waste of time then I'll just have to wait until I can afford a HSF, but I'd still like to try just for curiosity sake
