actually the hxc isnt terrible for the money. its based on the headphones takstar pro 80 which is considered as a good value choice just like the superlux 668b's are. not familiar with the model you have. the soundcard that comes with the hxc2 though has been plagued with problems so i wouldnt have suggested it anyways (the headphone portion is still good though).
yes, external soundcard, internal soundcard or software will work for you. just be sure it says dolby headphone (if asus card) or that it have virtual surround for headphones (if creative card)