It’s hard to know who’s good online, and this is a problem. This is a list to cover the US, Canada, UK, Australia, and other English-speaking portions of the world.
If you have any good online shops to add, PM me with the link(s).
If you’re not sure about an E-tailer, check Reseller Ratings.
United States
Directron
M-Wave
NCIX (USA site)
Newegg
SVC
TigerDirect (USA site)
ZipZoomFly
eWiz
Canada
FutureShop
NCIX (Canada site)
TigerDirect (Canada site)
UK/Europe
AriaPC
BigPockets
eBuyer
Komplett
MicroDirect
Overclockers UK
PlanetMicro
PowerUP
Savastore
Australia/NZ (thanks to pelvis_3)
Altech Computers
AusPC Market
GameDude
PC Maniacs
Plus Corporation
International
TigerDirect
eWiz