With my current HRT Music Streamer II+ to β22 to HD800 chain, I feel I've just about reached the point on the diminishing returns curve where it's no longer worth it for me to keep upgrading--my final setup. (We'll see how long it stays "final", haha) I am supremely satisfied with my current headphones and homemade amp, so I'm just looking to upgrade my DAC--partly so I can have two complete headphone systems with one to lend, and partly because I think I can do better than the MS II+ at my budget.
My ultimate goal is the most "revealing"/transparent headphone system possible. That has been a big part of my reasoning behind choosing the HD800s and β22, now I just want a good DAC to go with them. I am pretty ignorant of the high-end DACs that are out there besides the usual Schiit. My budget is around $1000, though I wouldn't mind going over it for something good. Recommend away!