Headphones

Depends on what you mean by satisfy: "endgame", no more buying headphones (doesn't exist) or "i could live with just this headphone forever".

Beyer DT990 Edition, never regretted buying them, never missed anything about them. (will still upgrade to DT1990 Pro if they break)

fully satisfied, though? I got small closed on-ears for outdoors (DT1350) and wireless ANC for travels..

And my Grados, just because I fell in love at the store. 😬

64 audio tia trio (IEMs)

So far, it's still the AKG K712 that I tried out at a hifi show - vastly preferred it to the Sennheiser HD650. While I also tried the Meze Elites in the same event, it's way out of my wheelhouse even when I enjoyed it as much as the AKG

Will be copping a pair of K712s once I update my setup

There is no headphone that satisfied me fully. No headphone is perfect. There is always some weakness.

I used AKG 553 for a long time. Then, recently I got the Fiio's FT3 and I am super happy with them. I dont think I will be getting another pair for a very long time c:

Grado SR80X with the large G-cush pads. I have a pair of HD600’s aswell but the soundstage is lacking even if clarity is better on them. Like them both a lot anyway but would happily live with my Grados for the rest of my life

Porta Pro. Also really want to try Meze 109 Pro. But I think the treble is going to be too much for me.

Sony MDR-MA900. For a long time nothing dethroned my KSC75x on a Porta Pro band, not the 6XX or the Tygr300r. These are a bit older but they are so light you barely feel like they are on your head. They are also the first headphones I have used that go over my big ass ears comfortably. I use them for everything. The bass is punchy and the treble is present but never shrill. The only gripe I have is that the cable is like extra long but I think a cable mod is in its future. Maybe I will make them balanced but I don't know if that will mess with the sound signature.

HD560S

I have big ears and Most headphones squish my ears against my head and it hurts after a few hours. Sennheiser are the only ones that fit and my HD559 are great for gaming.

None of the ones I own.

HD800

Sennheiser CX180 Street II. If I had them now, I’d still love them.

I got ZMF Aeolus for a bargain price, they’re perfect

Grado GW100 v2. I love it when wired! And it's good when BT too

Hifiman Ananda

My 109 Pro's are by far my favorite also. If I didn't own those, I would say my Audio Technica ATH AD 2000x would be in second place.

DT990s were great for years until they literally fell apart. Aryas now are amazing.

Focal utopia

HD560S + EQ.

Once EQ is factored in, I find the biggest differentiators are comfort, soundstage, imaging and bass extension. The HD560S does really well on all those and that's why I love it. My LCD-X does well too, except on comfort. So I often prefer to use the 560S.

AKG K702

Portable: Alessandro MS1, Full sized: Audeze LCD3

The hd580 that sounded fuller than both the 600 and 650, and not the second hd580 that sounded just like a 600

Audioquest Nighthawk. I wanted them for a long time. I like warm, fun, a bit of bass but not too much. Heard they were a little odd sounding. Found a gently used paid in box with extra cables. They were a bit odd sounding at first, not regretfully, just something I just couldn't put a finger on. But after a week or so, I'd go back to my other headphones and they all sounded so blah, recessed mids, unnatural, and lacking detail, or too bassy. These did it for me. Going on a few years now I guess.

They're discontinued and I couldn't find oem pads, but recently replaced with angled sheepskin. The oem pleather were more buttery soft and comfortable but these replacements don't seem to alter the sound. Something I really like about these is that they're semi open back. It seals well and noticeably cuts down on some external noise better than full open back. Some years back I was really into closed back cans but the natural sound and sound stage you get with open (or in this case semi) is real tough to get with closed.

From here, I was going to go with another dynamic. But I just don't know what an upgrade would look like. Meze 109 is probably a sidegrade. Focal Clear perhaps. I don't own a planar, so that's interesting too. But to my knowledge, and listening to mostly art rock, jazz and classical, but sometimes electronic, I don't know that planar out plays dynamic drivers. The Monoprice 1570 looked good to me.

Bought one pair and I think I'm good 👍

HD598.

HD 6XX

HD6xx after 20+ years of audio journey. My endgame, truly.

Some other notable ones (most I still have and keep) are: HD595, HD58x, DT770 32 Ohm, AirPods Max, XM3s

HE1000se

Hifiman he500, I would like to try on the he6.

Sennheiser HD800, it’s the pair that made me quit the hobby after all. They had nothing I didn’t want and everything I was looking for.

Neumann NDH 30. I had Sennheiaser HD280 Pro and HD595 before and was always disappointed in both. Got these and haven't looked back. I absolutely love them in every way you could love them. Comfortable and accurate, and my god that transient response...

They won't be for everyone, but for my purposes (semi-professional recording and mixing for music, post, and VO) they are wonderful. They are a treated room unto themselves and don't require any software to "fix" them. All my mixes translate better than even my monitors, to the point that my monitors are there to check against the headphones and not the other way around.

I really like my Audio Technica ATH-M50x's. I don't need an EQ or an amp with them. My almost-issue with them would be the soundstage, but even that isn't bad.

ATH-M50 headphones. Then, it was all downhill from there. lol

Campfire Cascade. Yes, bass cannons, but so much fun to listen with.

Sony MDR-Z1R

DT770pro never went above that (from buying perspective) but have tested a lot of headphones. I just love them and don't see any reason to switch in the next 5 years, except they brake...

To be honest, my 598s are the most comfortable thing I've ever had on my head, feels like I'm wearing pure air.

Only shame is that they leak the metronome sound when I'm trying to record guitar, so I need to keep my metronome pretty quiet.

HD560s

Hifiman Ananda was nearly perfect, but it needs a bass boost from the Ifi Zen DAC to make it perfect for me. But, in full agreement with the OP, the Meze 109 Pro is the first completely perfect headphone that I owned. It's extremely comfortable, it's gorgeous, and the sound is as smooth as can be. I don't think the treble is too harsh. TBH, I'm not sure why anyone thinks that. The 109 Pro is just warm and lovely. There's a tightness to the sound that is difficult to describe. It's not like a planar with the crisp, fast transients, but it's close to that. There's something very satisfying about the quality of the sound. Especially with acoustic music and blues! The 109 Pro is a masterpiece!

Koss Porta Pro 2000. Died many years ago but still my favourite.

I think speakers and headphones is one of those things you can replace if the sound gets boring. I’m on a beyer 1990 pro now and it has some benefits and drawbacks from previous headphones, but I like the mixup in listening to stuff through new devices. With screens there’s constant updates to make stuff look more and more accurate to reality. With audio there’s too many variables as sound depends so much on the phyiscal properties of the space they move through. So it’s cool to just change things up at times.

Atrium

AKG K92 were pretty nice.

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.