Hi gizmo,
It mostly depends on what you use your PC for, and the sound outputs you have.
For DCS only, your mobo integrated output is probably enough for DCS.
If you watch vids/movies or listen to HR music you might want to go for either dedicated soundcard or USB dac, whatever is more convenient for you (no need to spend more than 150 for either option, exceot if you want to setup an Hi-Fi system )
Again it all depends of what you do with your new PC
My soundcard is a Creative BlasterX AE-5 Plus, outputting to active speakers and it works great