Hi there,
for me the whole headphone topic escalated quickly during the last few months...
So, from old to new in this case:
- ~15 years ago
Sennheiser HD 555 (use it on my digital piano) - Plastic bomber, muffled sound but OK for the Piano.
- ~10 years ago
Koss Porta Pros - Well what can you say. They are amazingly light, are comfy and sound great for their price
- ~ 6-7 years ago
Denon AH-GC20 - My first ANCs. Never use them any more. Overly boomy bass. Should have sold them long ago.
- ~ 3 years ago
Sony WH-1000XM2 - My second ANCs. I liked them a lot when I bought them. But they are too small for my ears and produce noise when no music plays. Randomly use them for TV. They loose so hard when comparing to anything on the bottom of this list.
- November 2020
Sennheiser HD660S - Starting to fall into the rabbit hole. Whole different level. I`m lost... Beginning of the end 
- Januar 2021
Focal Clear - OK these will be my last set of headphone I will EVER buy... Love them. Very comfortable, very nice build. However...
- March 2021
Hifiman Aryas - All the good intentions (see January purchase) are gone. My first planars. I love them even more, and they are my absolute favourite as of today. The sound is just amazing. I had no clue, that "stage" does make this much of a difference.
Besides my personally owned stuff I have various headphones / headsets from my company in use: Airpod Pros, XM4s, Bose QC35II...
In parallel to the HD660S I started to invest in DACs and a headphone amp too. But that's not for here, I guess.
Cheers from Germania,
Markus