Toshiba, Hitachi, and NEC have come out with thier own methods
of liquid cooling their own range of laptops. They run a fluid line
over a wide area behind the LCD panel to cool the fluid and pump it
through an area in contact with the processor. Their main aim of
using liquid cooling is to make the laptops less noisy with the
reduction of fans, although a cooler processor is said to run
better.
For a home-based cpu, if sound isn't the main consideration,
recommend the use of sufficient fans and good ventilation is more
than good enough. If you really want to go all out, come out with
something that ducts air through a R-134A evaporator coil, but then
you'll need a compressor with a pump and thats where it'll turn
noisy again. 
