Generally with PSUs Antec is one of the best
Hard drives I would go with Seagate myself
RAM is a tossup between Corsair and OCZ
Video cards are xfx, bfg, or eVGA (couple others)
Cases the popular ones are thermaltake, I myself have an X-Alien
Processor these days for Cutting-Edge are Core 2 Duos, for still standard would be AMD or AM2 (if you do not want to spend a fortune on the Mobo and RAM)
Mobos are generally ASUS or some other brand (I like ASUS myself)
Sound cards are generally onboard, do not know many people who go spending cash on actual cards.
I think that is about it, if I missed something someone will catch it =)
Also, those are not all of the brands, just the ones I have personal experience with/are told are fabulous.
"Truth is violated by falsehood but outraged by silence."
"Mastering others is strength, mastering yourself is true power." ~Sun Tzu
"Ad Astra Per Aspera"
"Our greatest glory is not in never falling, but in rising every time we fall." ~Confucious
"The true measure of a man is how he treats someone who can do him absolutely no good.” ~ Samuel Jackson
“Omnis vir est fortunae faber”