Interesting discussion.
I've been through many speakers, some of which I liked a lot but I developed 'fatigue' over time; as much from the tweeter (I think) as with port chuffing.
Age hasn't helped I think.
I now own 2 pairs of speakers that I really enjoy listening to for long sessions: 1) Triangle Comète 40th anniversary with a 'Magnesium Rose Horn' tweeter: smooth as silk and a lively speaker that throws a wide soundstage. The second pair are DIY SEAS A26 clones. Not the last word in detail and extension, but they 'sound' just so right and I know what went into them: the cabs are made of Birch plywood and are nice and solid; the capacitor is a metalized poly cap from Solen; the SEAS A26RE4 woofer and the SEAS T35 tweeter that Troel loves. If anything ever goes wrong with the latter, I'll know exactly how to repair it! LoL.
Speaker in the past that had that same 'I can listen to it all day' type of sound: An old pair of Mission 710; a pair of smaller Mission Leading Edge speakers. I'll throw in Harbeth P3ESR and NHT super-ones 2.1; Mirage OM-10.