The best speaker you ever heard?

In my opinion, the speaker is by far the most important part of the audio system. After all, it is the only part you hear. OK, the other stuff really matters a lot, but without a great speaker... No go.

I am a bit 'speaker-obsessed' I guess, and now I am wondering: What are the best speakers you have ever heard, and what made them the best?
Melbguy, great post. Thanks for sharing. I listen to the Magico's a bit more now and have heard a few of their models, but don't remember all the numbers. With my MS, I can't always remember the model names. Some yes, some no. I usually remember the price ranges. I honestly am not sure if I've ever heard them set up properly. I think some dealers just have lines they like, but they don't always go great together. Even at the upper line of components I've seen/heard this at most shops. That's the biggest reason I drive 2 plus hours to support someone. I have plenty of shops near me and they are all very good and have good component, but I've yet to hear them at their best, so I wasn't able to hear what I want out of them, which is music. I want emotion. I recently heard the Genesis 2.2 and didn't love them. They sounded good and all, but the highs were bit too emphasized for MY ear and they weren't the most coherent. That may have been set up, but he said that he FINALLY had them dialed in. They just made everything we listened to sound BIG. Even Jazz at the Pawn Shop sounded like it was in a huge venue and it's a small place kind of like the Blue Note in NYC. That's what I listen for in some of these SUPER SPEAKERS. I honestly haven't liked any of the speakers over 100k that I've heard compared to the same companies speakers under 100k. I haven't heard all by ANY means, but I've been able to hear many within the last year or so. I have some friends who are well off, but not audiophiles and have no idea what they have other than something really expensive and big. I wonder how many of the engineers actually still hear lot's of live music these days. It's nice to have some great choices though.
Interesting comment Ctsooner...I have heard a few people whose opinions I respect make a similar comment: bass integration and image size. I suspect the former is setup but the latter I cannot say. I was amazed by the Genesis 1.1s when I heard them. I don't focus on image size too much...I rarely even listen in the 'sweet spot' since its an open-plan place. Nevertheless, I can understand it is an important element...and if it 'super sizes' everything, that raises a few questions.

if I ever get to hear them again, I will pay attention to both more carefully.
Von Schweikert VR-4 MkII with the 5 mod from the factory. Clean sound, articulate, spatially accurate, intimately satisfying on small groups or solo. Sounds live like real music does. Real music like an orchestra the sound is a bit jumbled, separation in real life is an artifact. That's what I hear when I listen to VS VR-4II with the 5 mod.

I have had Vandersteen 3asigs, 5 sigs, Usher, big Fried transmission lines called the Super Monitor. Electrostatics ML Source, Acoustat Mod 3s. Would not trade any of them for what I have now.
Atmasphere, thanks for your informative post. I understand the logic of using the rated efficiency and impedance to determine actual efficiency, however in your comments you have not considered the phase angle and impedance dip of a speaker and how that can influence the load presented to the amplifier. The Infinity Kappa 9's for example had an amp-crushing 1 ohm dip with a severe phase angle which literally made many amps go up in smoke. Just my 2 cents.