i would not say much, but if you are going surround[5.1/7.1] I would prefer to go with a surround speaker setup rather than headphones.
I kind of a taste for stereo headphones. Here I am talking about top quality. 7.1 speaker setup will be costly, but they will be worth it, where as in a headphone, it wouldnt give you any good audio entertainment.
But if situation insist you on getting a headphone[eg: not to wake your neighbours up] than you can go a headphone setup, but here I would still prefer stereo over surround.
and here is a phoebus article
ASUS RoG Xonar Phoebus 7.1 PCI-E Soundcard Review