Hard drive: Western Digital "special edition" 80gb 7200rpms. Cost: $80.
RAM: Two sticks of 512mb PC2700 Kingston sticks. Cost: $138.
Sound card: Sound Blaster Audigy 2 platinum. Cost: $167.
Coming together... Make sure to go to the third page of the Audigy review, to check out the shiny drive bay extension, with many connections and dials I'll probably never use. ;)