3 - HD598
2 - MA900
1 - PX100-II
T1s for me...I'm big on physical comfort but also on how well the pads breathe...the T1s keep my ears nice and cool and I can wear them quite a while. My Grados have average comfrort except for the 80s....once you soften up the pads they are very comfy, light headphones that have very little clamp and just rest gently on your noggin. Least comfortable would be the Sennheiser 518s....those things were like a sauna on my ears.
I dont have anything to compare to, but i have a pair of Bose AE2's that I have worn on 2 overnight flights to Hawaii.That is 8 total hours of nonstop use (flight time, not layovers. Actual user time is probably around 8 1/2) and they are like lightweight pillows on your ears. I didnt experience any discomfort.
I know Bose isnt well liked because of the price tag, but I see why they appeal to older people. They may be pretty expensive but they don't really have any cons, and they do the little things perfectly. I like them a lot, just not well enough to keep them :) (trying to sell to get a pair of HFI 580s)
The Bose AE2 is marginally more comfy, but the M50 smokes the other two in comfort.
How did you find they felt different compared to mine? Maybe yours are more "broken-in" lol. I'm very ocd with my stuff, so it's pretty much stiff as it would be out of the box.
Another super comfy set of mine is the Koss Reference One. It has hard vinyl earpads and clamps a lot but it feels like a pair of huge, cozy earmuffs when you're wearing it.
It is very heavy though (over a pound) so I don't recommend it for constant use, and it's not like you'll ever find one... they're stupid rare.