Systems I will use. I am a gamer, so my main rig is my pc. Xonar ST (very sweet sound card, best i have ever heard) and a Sound blaster recon3d, I switch between cards based on my mood.
For portable I use my Lg Spectrum 2, sometimes with a Xenos portable amp.
My better headphones on hand are a Hifiman he-400, a Philips fidelio X1, AKG K550 and K612, and a sennheiser momentum.