Started a year + ago with a pair of K701 which I still have and like very much. Than I got a pair of K702, just to find out myself is there really no difference between the two of them. Unfortunately, I still dont have the apppropriate time slot for that. Hopefully during the season's holidays.
DT880 (600Ohm) - still burning in
K1000 - never heard anything better myself sofar
on the way and due to arrive in a matter of days is a set of SR007MK2/SRM727 - great expectations in this direction.
I would like to try Grados - RS1 and GS1000, and of course I would never say no to trying some more of the "royal family" - HE90, R10
Tho I am enjoying my HFI-780 that I had for a while, I still wish I could have had the Pro-750's even tho I Couldnt afford them. I do even want to try some DT880's just to see how I would like them in gaming and music/Casio Wk-110.