For me as you go higher up the chain the "holy ****" moments become few and far between - though I have not heard any of the full-sized flagships yet. Maybe something that you enjoy listening to music from will suffice, rather than looking for the next audio revelation which may or may not exist
That being said, I'm looking at picking up the AD2K as my first full-sized cans as well - been doing a ton of reading and these really interest me, especially their ease of drive. Do they really sound as "wrong" with classical as the opening review suggests? My music is part mellow female vocals, part pop/electronica, and small part classical. Will they run fine out of an Audinst HUD-MX1?