While I didn't own the following speakers mentioned, they had a lasting impact on me:
Yamaha FX-3. Heard them at a local dealer in 1980 with my brother and father playing the then recently released Pink Floyd double LP 'The Wall' - "Another Brick In The Wall, Part II." I was 8 years old, and at the time already being very interested in sound reproduction they blew my mind.
Some 4-5 years later, Snell AII's. My first acquaintance with a stage, coherency and timbre of this kind. Lovely speakers. The later AIIIi's were less convincing to my ears.
Around '90/'91 I heard a pair of JBL K2 S9500, and was astounded by their explosive dynamics and clean, visceral presentation. I was already quite familiar with the sound of larger JBL models like 250Ti, 4430, 4435 and Everest DD55000, but this was something altogether different. To date the most dynamic JBL domestic line speaker I've heard (incl. the Everest DD67000), no doubt aided by the crazy powerful 1400ND (first neodymium magnet) woofers, Bessel tuned.
S.P. Technology Revelation + dual EV TL880D subs, some 10 years ago. The interesting takeaway auditioning this speaker setup was that I heard the transformation from their original passive configuration to a fully active ditto, which convinced me of the natural attributes of going active and that it was even possible this way
That effectively settled my audio path going forward some years later pursuing active configuration myself, though "married" with a different approach in speakers more in line with and inspired by the K2 S9500's mentioned earlier, which is to say large, dual pro style woofer/mids and compression driver/even large horn as a 2-way main speaker setup, augmented with a pair of tapped horn subs.