I certainly regret selling my Cabasse Atlantis speakers. They were the ugliest things ever created ( 8ft. tall with a huge eyeball protruding from the pyramidal front) but they were amazing transducers. My wife made me choose between them and our marriage, and I chose poorly.
Speakers you regret selling
I was lucky to own Sonus Faber Extrema, Acoustic Energy AE1 Signature, and Dynaudio Confidence 5 in the past. They are rare in used market and can make any owner happy for the rest of his/her life. So I swore to myself I would never sell my Sonus Faber Amati this time though my wife has heard that a million times. What did you regret selling?