For my AMD64 3400+ and Radeon 9800 XT, I'm using a combination of Nexus Breeze 400, Zalman Reserator 1 (fanless watercooling) and Zalman ZM-GWB1 (water block for graphics card). Full specs are at http://www.orfjackal.net/pc.php
Right now the most noise comes from the hard drives (160+250GB...