That's a good question and you'll probably get a variety of responses. My personal experience is that a CD 'fully tweaked' still sounds the best. 'Tweaking' is an art/science which can include a cleaning agent such as Optrix or Shinola, demagnetizing with a device such as the Bedini Clarifier, beveling and painting the edge, etc. I typically use at least a three stage process before a serious listening session (sometimes more). Most of the really good tweaks are cumulative meaning that the sound keeps getting more resolved and involving with each step.
Other digital sources can be really good as well, but the CD remains the 'hands-on' favorite for me.
Other digital sources can be really good as well, but the CD remains the 'hands-on' favorite for me.