totaly fanless case
 

not sure if anyone has seen this before but it looks pretty interesting, uses heatpipes to transfer the heat to the case which is a giant heatsink, not sure how good it would be for a gaming PC, but would be great for a home theater system since you don't really want to be listening to the wining of the fans when watching a movie

http://www.directron.com/fanless.html

Very cool concept, but looks extremely difficult to manufacture. I estimate it won't cost less than $500.

It might just work too, but thermal resistance isn't going to be good... even if the CPU exchanger is efficient, the interface between the heatpipes and the case side has to be perfect.

I had once thought of using the same concept, but with real (water)cooling. Think of the same case, but with channels bored out in the heatsink base. Then connect the channels with tubing, hook up a pump and wb, and enjoy fanless cooling and good performance.