Since motherboards can vary in the CODECs they use, it would be better to read about the CODECs that are high quality. Most vendors like NewEgg will list the Audio CODEC in the board specs. But you can also check the manufacturer's page for the board(s) you are considering.
This is a good reference, but some of the most recent CODECs aren't on it. Still, a good starting point:
http://www.hardwaresecrets.com/article/Audio-Codec-Comparison-Table/520
If you plan to use high end headphones, you also want to look for one that has a high quality amp. For example, I think the Asus Crosshair or Formula series has a 600 Ohm rear panel amp for headphones, which is good.