General Benchmarks that compare A to B of the most popular hardware for various setups, games, settings, resolution, etc:
AnandTech’s Bench
&
Toms Hardware Guide – Charts

The best Power Supply (PSU) Reviewer:
http://www.jonnyguru.com/modules.php?name=NDReviews

The best CPU Fan Reviewer:
http://www.frostytech.com/
(here is my spreadsheet of his data, which is easier to navigate than his page if you just want data, the columns sortable)

Best Monitor Reviewer:
http://www.tftcentral.co.uk/

Other benchmarks/hardware review sites. Browsing them is not as effective as Googling for something specific:

http://www.legitreviews.com/

http://techreport.com

http://hothardware.com/

http://www.legionhardware.com/

http://www.hardwarecanucks.com/

http://www.overclockersclub.com/

Nitch:
Silent computing, quiet case fans, etc: http://www.silentpcreview.com/

What reviewing does not get adequately done:

1. Reviews for Optical drives are almost unheard of now.
2. Good A:B computer speakers/heaedphones are impossible to find (too many offerings)

Not good PC hardware site that think they are of value: Cnet, PCMag, Passmark’s benchmarks (but they are good ballpark)