The very best sounding systems I've heard were horn-based systems either using original Western Electric drivers or G.I.P. reproductions of such drivers. This means truly ancient technology, basically, early 1930s drivers. Most of the systems were modern assemblies using these ancient parts (or replicas of these ancient parts). The big downside is the size of these systems.
For one of them, each speaker was about nine feet tall, almost five feet wide, and about five feet deep. The drivers were new G.I.P. drivers that retail for about $120,000. On top of that would be the fees for designing and building, the very expensive crossover utilizing original Western Electric parts, the wiring (I believe the wires were a mix of Western Electric wire and Audio Note Sogon (meaning wiring well north of $20k), and the custom-built power supplies for the field coil magnets of these drivers.
My much more modest horn-based system has only one horn component, a midrange compression driver and a sectoral horn. I don't have horn-loaded bass drivers, my bass drivers are modern, but old school alnico magnet drivers with pleated paper surrounds (12" drivers), with two bass drivers per channel in an Onken bass reflex cabinet. My tweeters are bullet tweeters (horn waveguide, but not a compression driver).
But, I have also heard very nice speakers of all sorts of types, including very good panel and line array speakers. The giant Sound Labs electrostatic panel speakers are quite good. Likewise, the Arion Acoustics line array speakers, while quite pricey, are terrific too. For more realistically priced line array speakers, I like Maggies, such as the 3.7.
