Well I hope the title captures what I'm looking for.  I've got the beyerdynamic DT 770 pro headphones, JDSLabs O2 and a soundcard with sp/dif output.  I'd like to combine all of this and I think what I'm missing is a good DAC that accepts SP/DIF (should be cheaper/easier/better than usb, yes?). ...

  Well I've decided I want to get something nicer than my crappy headset which I wear quite a bit for gaming.  I've been looking at some DT 770 PRO 80 ohms, they need to be super comfortable and that's what I hear you get with the Beyerdynamics, plus I have heard that the 770s have good bass...