Lots of great reading on this thread! I think I'm finally caught up with the posts (whew).
It's taken a couple of years, but I finally have my complete Schiit setup at home and at work:
At home I'm alternating between a Gungnir + Mjolnir combo with balanced Senn HD650s and a Gungnir + Lyr combo with AKG K712 Pros. Still deciding on the tubes I like in the Lyr. At work I have a Bifrost Uber + Asgard 2 into a pair of VMODA XS headphones (need to keep it quiet at work, and I like that I can take the VMODAs with me on-the-go...).
So far I'm extremely happy with both of my setups, but I'm still working on developing my "ear" for all the subtleties. The HD650 chain I find to be deeply engaging -- even intoxicating. The AKG K712 chain with the Lyr is a lot of fun to listen to, especially while swapping tubes to discover the nuances of music I didn't realize I had been missing.
Might I be missing something with my setup at this point? A mismatch perhaps in gear? I know I could get more out of the at-work setup with a better set of headphones, but I need a closed, over-ear pair (i.e., that nobody near my desk can overhear as it's rather tight quarters). So, I'm still exploring the head-fi forums and online reviews for pair that will best compliment the Bifrost and Asgard.