Primary Desktop Rig: Sound Blaster Z sends optical signal to Bifrost/ Asgard 2 with HD 800..
Secondary Desktop Rig: Sound Blaster Z sends line out to Matrix M-Stage with DT 770 (250 Ohms) or whichever other headphone.
(Both signals play simultaneously in the event of a second person wanting to listen.)
Bed rig: Audioquest Dragonfly out of laptop to HD 598's.
Portable rig: HD380's with my Samsung Galaxy. But I almost never listen on the go.