The best speaker you ever heard?

The best speakers I have heard are the big Analysis Amphitreons. They are an easy to drive planar speaker with a long ribbon tweeter. I have a smaller pair of analysis speakers called the epsilon that do most of what the larger ones do, but not all. I have heard them driven with 100 watts and they were fantastic.

Simplicity oh Grasshopper. Wharfedale Diamond 9.1. This message approved by H.D.Thoreau.

AERIAL 20T V2

I've owned many different types of speakers over the years including single driver horns, Quad ESL57's, expensive multi-driver floor standing speakers, modified klipsch LaScala speakers, and several home built speaker kits. The best that I've heard with my Shindo Labs gear has been the Tonian Labs Classic 12.1's that recently played at the California Audio Show in San Francisco. These speakers have a single driver PHY HB30L15 driver paired with a Tonian Labs ribbon tweeter. The speaker is 97db - 16ohms and does not require much power to drive it. I've found that a good 300b amp is all you need to make wonderful music with these speakers although they also sound amazing with various types of amplifiers.

Ive never heard it yet and it doesnt exist also, but it will be a speaker with all syn. diamond cones i reckon , up to now Thiel accuton makes one of 50 mm diameter maximum as they are hard to manufacture , but i think a D 20 mm tweeter and a D 50 mm midrange and 2 D 200 mm for bassresponse will quite cover the audio bandwith for not big a room .
And that sound will be something , considered all otherdesignfeatures are well taken care of , it will also be damn expensive