I think I'm going the "giant passive Zalman water radiator" route for my next build, but these are interesting. I'm just not convinced that fanless is a realistic build choice for cost, safety, and performance reasons.
Mostly cost, actually
I've been thinking about a fanless system for awile and it seems rather impossible if you want the latest and greatest. This Hush PC speaks quality to me and is a very good deal IMHO. Problem is I don't see a pentium @3.6 or a FX-53 @2.6 in there nor do I see FSB of 250+ or an 5950 or 9800xt:)
Anyway if you want to build a silent system and overclock I recommend heading over to highspeedpc.com and picking up the following:
-XX Flow water block for the CPU.
- Dual convection rad setup using the Konvekt-o-Matic Coupling System.
- Chipset block: Graph-O-Matic Rev2.0
-Video Card block: Cool-Matic ATi rev1.5
-Ehiem 1048 or DC model both are silent from 6" away.
Simply mount these great looking rads to the side(s) of case, plumb, and you're off.
I believe you still need *some* air flow though case for mosfets, caps, memory and other IC's and this could come from the PSU with the entire case acting as a shroud. The ones recommended by Mikec would be good here.
As far as the passive Zalman system I've seen no good tests and one I did see it performed aweful. Not only that you have this cylindrical "giant" tube you have to leave out in the open so convection actually works. Also not very convient if ou want to move case...Basically I don't expect much from this.