PC360 connected to the Titanium HD Headphone out and Mic.
Stereo-Mix over SPDIF enabled towards my DAC.
I only need the PC360 for multiplayer purposes with Skype/any other Voicecom. Volume is at about 25-30% when using it.
Since I am quite the immersion fanatic (playing SP primarily) I want to play my singleplayer games with the best I have, in that case the HD 800 and generally you maximize the volume of the source and leave volume changes to the amp. Since the PC360 is connected as well, a volume level of 100% on the X-Fi makes them quite loud of course. Luckily you can dial it back via the knob on the PC360. Unfortunately it is not able to fully dial the sound down and can be heard across the room.
Of course this is more of a luxury problem, but I have the Silverstone Fortress Case under my desk and it's mainboard installation is rotated by 90% so all ports and connections are on the top of the case and I have to put the PC360 connections blindly if I'd disconnect them every time. It's rather annoying.