Motherboard:
Asus
DFI
MSI
Processor:
AMD
Intel
Motorola?
Hard Drive
Western Digital
Seagate
(I only get Seagate)
PSU
PC Power and Cooling
Enermax
Antec
OCZ
Fortron
Optical Drives
(You'll get ALOT of differences in opinon here)
Lite-On
NEC
Plextor
Graphics cards:
ATI GPU's :
ATI
Sapphire
nvidia GPU's:
eVGA
XFX
MSI, gigabyte, BFG. lol
Memory
Corsair
OCZ
G.Skill