General digital photography sites

DPreview
Rob Galbrait
Luminous-Landscape
The Digital Picture (with lens comparator)
Imaging-resource
photo.net
techphoto
FredMiranda
Juza Photo

Hardware

Canon camera and lenses

Canon Camera Museum 
BeBit
EFlenses CanonUSA 
Canon EOS
Response curves : D30 | D60

Lenses

MTF tests

Photodo  
MTF tests of Canon & Nikon 300 mm lenses
Lens Comparometer

Other lens tests

Juza Photo Lens reviews
Castleman lens reviews
Photozone.de
Westfall graphical of Photozone
16-9.net wide angle tests
Macro lenses compared
Sharpness with/without teleconverter
Oleg Kikin lens test links

Autofocus at >5.6 (or >8.0)

dlcphotography
FredMiranda
dpreview1
dpreview2
a1

Portable storage

Upgrading hard disk of MindStor (MS) or Digital Wallet (DW)

Batteries

Imaging-resource NiMH comparison test
The Battery University
NiCad Battery Zapper

 Canon versus Nikon

Naturephotographers  
Poelking  
Camerahobby  
10D versus D100

Computer

Graphic Cards

Tecchannel signal quality comparison test 

Film Scanners

http://www.cix.co.uk/~tsphoto/tech/filmscan/menu.htm

Computers general

Rob Galbraith comparison of Mac versus PC | Updated
Haxial on Mac G5 marketing 

CD or DVD storage

PADI 

Software

RAW conversion

DLC on Hardware and Software Tools
NeatImage

Image editing

Correcting Distortion and Color Fringing 
Understanding image sharpness part 2: Resolution and MTF curves in scanners and sharpening by Norman Koren

Some panorama software - http://research.microsoft.com/en-us/um/redmond/groups/ivm/ICE/

SwissArmyFork
Microsoft ICE

Scanning

A few scanning tips by Wayne Fulton 

Other

D30 to a Nikon 5000 noise comparison