For the best overall headphone results, balanced is a must, not single-ended. The CD player and headphone amp must be balanced also, externally and internally, or a balanced personal player.
My go to phones at the moment are Audio-Technica W1000Z (aftermarket balanced by Surf Cables),
Audeze LSD-3's, and Sennheiser Amperiors (balanced cables). The A-T's are good for up-close
imaging and higher Hz's, the 3's good for lush audio, and the Am's...