HD-600 and Asgard
Beats Pro and WA22
Matrix M-Stage and K702/K701/Q701
My personal favorite by far...
Headroom Micro Amp and Q701
Sadly it seems the Headroom stuff isn't as popular here as it was years ago..
BTW I also thought the D2000 and Asgard was pretty dang impressive.
Don't laugh...M50/D2000 with Nuforce Icon Mobile..seriously (that one's from me..and only if you love your mids more than treble/bass)
Somehow I never heard an amp having magical synergy with the HD-650? Why is this?