[clug] building computer

[freds73 at aapt.net.au]

I want to build a new computer  and am wondering where to buy the parts.  
Are there any companies in Canberra which have a good reputation, or
would you get the lot from a computer fair.
  Does a computer fair still happen at the exhibition centre or has it  
changed to be only at the university amenities hall?
  As I am not into graphics cards, what is the difference between a nvidia  
6200 and a nvidia 6600 card, the specs on the cards list the 6200 as  
having a faster gpu than the 6600, but lesser performance.

TIA
Fred