DAC or CD Player. Help!

Price of cable might not matter, but one cable can deliver better sound than another.  Cheaper CDP can sound better than expensive transport when feeding DAC.  That is synergy.

OP, if this is a way of asking if you should buy a dac or a cd player, I would personally recommend a dac in this day and age.  I can stream most of the music in the world through online streaming services and my own library through a dac that I can control using an app on my phone.

Everything in the audio chain can have an effect starting with the mastering of the original recording.  This is getting complicated, but even the phase noise of the clock generator in your cd transport/player and the clock used in your dac has an audible effect. 

Regarding synergy, there has to be some intelligent decisions made when selecting audio components.  For example if you don't like bright / harsh sound, you wouldn't pair a bright sounding dac with bright sounding speakers and use silver plated cables - ear fatigue nightmare!

Worse than the AC cable snake oil is without doubt the cable risers. Spend major bucks on foo-foo cable jackets and 'flex' mesh pixie powder that they slip over the three-layer cable jacket only to determine that if the cable lays on the floor the sound is diminished. That's not synergy, it's idiocy.