I mentioned earlier in the thread 2 speakers that wow'd me:
Waveform Mach 17
MBL 101D
Those were two instances were it wasn't just "Boy do I ever like this sound!" but really a sort of breathtaking experience, a level of shock value.
The first was hearing the MBL omnis in a reviewer's home (a TAS reviewer) where he had them in a very small room, with lots of room treatment.
He played a selection of tracks and, until that point, I never knew that such sound was even possible - some of it more real than I'd ever encountered, some of it just sheer neato pyrotechnics.
I heard the Waveform Mach 17 at John Otvos' home (he ran the company - it eventually folded). It was at a time where I had literally travelled far and wide hearing most of the hyped up speakers of the time (including big Wilsons, Genesis, you name it). Otvos was an early devotee of "prove it with measurements" and developed his speakers using the Canadian NRC facilities. He sought neutral on-axis sound with smooth even wide dispersion. The Waveform speakers were immediatly identifiable at those times by their egg-shaped midrange/tweeter module, made of super dense material. He demonstrated his tri-amplified speakers to a friend and me, using cheap solid state amps and off the shelf cables (he thought the cable market was a scam, same with expensive amplifiers, as well as tube amps). It was shocking. The Mach 17 in that demo seemed to combine practically all the impressive qualities of other speakers in one speaker: an electrostatic like "disappearing" act, yet dynamic and propulsive like no electrostatic I've heard, capable of enormous dynamics for church organ, orchestral spectaculars or dynamic pop music, while also being tonally even and neutral sounding. It's like they did what most other speakers were trying to achieve without sweating.
I don't mean to say they were actually perfect speakers. Only that, at the time (1999 IIRC) they blew me away.