After demoing a number of configurations, speakers, soundcards and headphones, I have something that sounds good to me.
I ended up with Audio Engine 2's, the AE D-1 and AKG 702's. The AE2's are quite surprising and the D-1 makes them shine. They are much warmer than the MM1's and quite accurate, at least to my ears. The 702's are probably a bit underpowered, but they are outstanding and extremely comfortable. I also added the AE speaker stands and they make a noticeable difference.
I am very happy that I found this forum, you all helped me a great deal.