@kmarc
i think he meant the "deadspot". the middle of the fan where the motor are, doesn't push air. if close contact with heatsink, no air pushed in that area. if u distance a bit between fan and heatsink, some air will pass through there due to space available for air to disperse. might sound confusing cuz i'm bad in explaining stuff lol

Ya, I know what he meant. The trade off is that the air flow's speed is less and a lot of air will be dispersed around the heatsink rather than through it.

Not only that, those air that disperse at the dead spot also comes from the fan anyway!!! 

Edit : Your explanation is not bad at all. "Deadspot" is the correct term which I didn't think about!!

Le, why didn't you mention the airduct earlier on???

Of course, with an air-duct, all the air that blows out of the fan will be channeled into the heatsink. That's no argument about that. In fact, I'm thinking about doing a custom made air-duct in a Y-shape configuration, so that it can accomodate 2 fans blowing air from 2 channels into a single channel before it hits the heatsink!!!

There's a discussion somewhere about getting cheap water-cooling stuff. All in all, the general recommendations is that if you want water-cooling, it is better to get a good one in the range of at least rm600-700. It is generally not recommended to get cheap WC setups..... 

My mobo is on lying flat on top of my casing so it would not be a problem for me. The air-duct is supported by the protruding heat-pipes at the top (no additional support needed)

Ya, was thinking of channelling some cold air from my air-con (through a tube that is connected to the air-duct via a side hole) but my wife would probably throw a fit!!! 

Errr.... your link didn't show any tube or anything? You're referring to the casing?