CPU: AMD Because it performs VERY WELL and is cheaper than its intel counterpart.
Motherboard: Gigabyte because they make quality boards with good options at good price
RAM: G. Skill because of the quality and price
HDD: Western Digital cheapest quality drive I could find
PSU: OCZ makes my Rig power up at a good price.
Optical Drive: Samsung cuz they spin my discs and put the content on my screen for me to access
GPU: ATI Currently HIS because who can turn down a 4870 1gb for 135 bucks?
HSF: Xigmatek just cuz I didn't want to take out a loan for a TRUE...
Case: Whatever looks super sexy, has a good price tag, and has good airflow.
Monitor: anything that shows my picture at a high resolution and doesn't break the bank.
Case Fans: Yate or Scythe will do just fine...
Yep thats about all I guess. So for the most part its the most quality at the price Im looking to pay. Maybe when I am rich some of the things will change...