Some speakers I have owned or listened to and lusted after:
Quad ESL57 - currently in storage, unbeatable purity of midrange... play a good TT into these with a QuadII valve amp or Quad 303 driving them, and they definitely do midrange magic. They are also delicate, and must be run with the right amp otherwise you can easily get fireworks and a speaker that does not do much.
Quad ESL63 - loses a touch of the midrange magic of the 57, but when positioned right they are a much more full range speaker, and the imaging is absolute magic - there is a sweet spot where it is pinpoint sharp, but you get real imaging right across most of the room - quite remarkable, and like the ELS57, the microdetail they can reproduce is astounding - not a "rock" speaker - won't give you that gut thumping kick drum.
Quad ESL989 - all the good things of the ESL63 - but more lower end, it just goes lower - also the mid panels are higher off the floor. Remains one of my reference speakers - brilliant!
Martin Logan CLS - heard these, liked them a lot, ultimately chose the quads - the Quads have the all over the room imaging effect, the ML's didn't do that - but I could live with them!
Maggie Planar 3.6 - heard these a number of times.... doesn't do the microdetail thing as well as the electrostatics - needs a bit more oomph to get things happening.... But it does not sound like a box. (on a lot of speakers I can literally hear the box) - I liked these, another speaker I could live with.
Boston Acoustics A400 - this one is a fabulous rock speaker, and does everything else well too - requires a good powerful amp - but ohmygosh it definitely could give you that gut thump sensation. - The rest of that speaker range was good in gradually reducing levels of quality - all of this series with the soft dome tweeter had a touch of magic (A400, A150, A100, A70, A60)
Klipsch Forte II - not one of my personal favourites - you need an amp that can give it some serious "stick" before it wakes up, and it doesn't wake up at lower volumes (which is why I didn't go for it) - but once it wakes up, this is another fab rock speaker, or one for BIG music. Yes it is an efficient speaker, but I never had any luck running it with lower powered amps - 100W minimum!
Gale 402's I remember liking these - got them for a friend who asked me to set up a system for him... but I do not remember what they sounded like!
Gallo Reference 3.1 - my current main speakers - a compact, non boxy floor stander with Gallo's CDT tweeter (effectively a supertweeter as it goes well beyond 20kHz) - with a 180 degree spread for the tweeter, this is another one that throws an image that can be heard from most places around the room.
It is not quite as good as my previous Quad 989's but it is a LOT more compact (which was the point of the changeover.... sigh).
DCM Timewindow - a friend had these and I remember liking these a lot - an omnidirectional speaker, with transmission line loading if I remember correctly - needed a bit of power, another forgotten speaker that occasionally shows up as a great buy.
Metaxas Electrostatics - I remember hearing this at Kostas Metaxas' Melbourne showroom many years ago, with a goldmund reference feeding into some Metaxas amps - the whole thing played one of the most "real" piano renditions I have heard.
Very very good - but I thought the ESL57's did the midrange a touch better... (but then to this day I think nothing matches the ESL57's midrange!)