Alphacool Xtreme Pro
 

Basically, water cooling produces better cooling results keeping the noise down. The Alphacool Xtreme Pro set did a good job because the fans and pump were very silent. When paired with powerful fan, the performance of the Alphacool Xtreme Pro set was awesome. The pump is powerful and with the aid of a voltage stabilizer, the 12V pump was able to receive 24V directly from the power socket. Besides, it was also easy to install and very secure thus giving me a piece of mind. If you are planning to go for a silent water cooling solution, then the Alphacool should serve you well - provided of course you have cash to burn because USD310 isn't cheap at all!

Link: http://www.pcmoddingmy.com/content.php?review.190