I think having a seperate transport and DAC. Each built to the highest quality standards available.
The Transport is very important in getting the data off of the disk and getting into an electrical form. vibration control, really good lasers, power supplys are all important
The DAC is where the data is changed from Digital to Analog. To me the "music" is created in the DAC from the information that it receves from the transport. Having a really good DAC has a lot of advantages, like you can connect other digital inputs and still get a very good Analog signel out.
A DAC that uses Burr Brown DAC's and butterworth filters are among the best there is. (DAC = digital to analog converter)
