Why? First of all the site is up to date. Also the tests of equipment are solid and there's detailed information about the types of noise and where they come from. Interesting stuff for sound engineers.
They tell you things like is the noise centered around certain frequencies or is it scattered evenly across the frequency spectrum? Can it be damped? Is it even relevant to damp it? Because it doesn't make sense to go for an even quiter pc once its noise is masked by other noises.
To give an idea here is the setup i came up with a year ago after checking out silentpcreview.com
Case: Antec P182 - it's got good airflow and damping and lots of space and it's very tidy inside
Motherboard: Gigabyte GA-P35-DS3R - relatively low power consumption means less heat, less fans, less noise
Processor: Intel Core 2 Duo E6850 - only get a quad core if you really use the extra power because it generates more heat
Heatsink: Scythe Ninja Heatpipe - Scythe fans are usually ok
Hard drives: Western Digital Caviar SE16 SATAII - relatively quiet
Power: Corsair CMPSU-520HXEU - just read the reviews
Only one casefan is enabled and still the temperature never rises above 45 celsius. The 45 degrees is typical for a warm summer day but on a cold day it stays well below 40 degrees.