So what is the best speaker you have ever owned?

The one's that I currently own...the Sonus Faber Guarneri Hommage's.
Not likely to be replaced any time soon, enjoying them too much..:0)

HI,
My Martin Logan CLS IIA's electrostatics are the my favorites. I've had them since 1988 and they have been upgraded to the "A" version. The panels were replaced about 1 1/2 years ago. They are driven by ARC tubes. I have dual biamped (Levinson No. 23) Kinergetics SW-800 subwoofers. An astonishing speaker array.

Sparky

Not much of a consensus here?
Just goes to show how different we all are in our tastes and preferences......and also why there are so many different speakers on the market?

Merlin VSM MX. Wonderful imaging,easy to drive,extended highs, surprisingly full bass, and very musical sounding.

Not much concensus, but some darn good speakers in the list. Inevitably, for most people, it is going to be the speaker you have at the moment, otherwise, why did you change it.
I have enjoyed a number of speakers listed above, Harbeth, Proac, Devore fidelity, less so some of the others. For my current set up, with a relatively low powered, Class A hybrid amp, the Daedalus Da-RMa monitors, tick all the boxes. Very fast neutral good imaging, look great etc