In the past it was the Fostex Purpleheart.
Never got one myself but a friend of mine who had them often gave it to me over some weekends. Never found anything similar in sound since today.

I demo’d some headphones at the beginning of this year and I really liked the sound of the Focal Elex. Sadly I heard a lot of bad things about their driver issues so haven’t bought them.

Still searching to this day for an easy to drive headphone with good detail, a really strong bass and somewhat a balance between sparkly and a bit of laid back treble. I’m sensitive if it’s a harsh treble but I still need a bit of it to make the music I am listening to sound exciting.
All the headphone that are fulfilling these criterias are simply way above my budget.