Best sounding headphones you have owned?

I love my Klipsch HP 3.   Don't use them often but they sound great.    I had some Grado RS 2e and they were excellent,   I ended up giving them to my son in law and he uses them all the time 

My first pair was over 40 years ago, AKG k240...   I still have them.   I had some nice Beyerdynamic too.   Currently my only pair I use  is the HP 3.    I'm driving them with the excellent Quicksilver headphone amp.  

My “old time” favorite: Sennheiser HD800 (original). With SDR mod.

My current TOTL headphones: Meze Elite. Happy 

You know, it is funny… I keep thinking it would be my Focal Utopia… but it is my Sennheiser HD800’s that I listen to by far the most… 95% of the time. I seldom listen to my Beyerdynamic T2, Audez LCD 2, Ultrasonde Edition 9, Denon 9000 (?)… or my other ones… Grado, ADG, Ultrasonde, etc… wow, I have a lot of headphones..

I think the Focal Utopia bested the Sennheiser until I upgraded the electronics to a tremendously powerful, natural, tube head amp.

Quad ERA-1

Stax Lambda SR (non-pro) here, I have been using them for about 30(!) years and although I have tried many others, nothing comes close for overall SQ.  I like the Utopias, especially for bass, but anything acoustic on the Stax is just amazing.