Everything considered, Gershman Avant-Gardes........
Well, three of the bigger names are Wilson Audio X1 Grand SLAMM Series IIA, Nearfield Acoustics Pipedreams, and JMlab Grand Utopia. Their reviews are very enthusiastic. If you're new to the high end, I hope you have the wallet to go for the top of the line stuff. You can get great sound without insisting on the "best." If you're willing to consider hybrid panel/dynamic speakers, there are some great candidates, too.
I think that Lowthers must be considered in this category. First, they are an extremely musical loudspeaker that does 36Hz- 22kHz on its own. Very nearly the entire range. Requires no crossovers. Has 100db/1watt efficiency in a cabinet. Handles 100 watts. When you say "DYNAMIC", a 100db efficiency will give you the SPL at 1 watt, that it would take about 32 watts to provide with an 86db efficient speaker. This efficiency keeps your amp in a lower power output level that sounds better(especially class AB, keeping the amp in the class A power levels), and provides gobs of dynamic headroom so you will probably never clip your amp, even on the most dynamic transient. It has midrange and highs that are sought after by the "golden midrange" high-end SET tube aficionados, and bass can go down to 32Hz(-3db) in the right cabinet. It is probably the most detailed speaker available in dynamic types, rivaling even electrostatics for detail. The single driver provides the truest "point source" for imaging quality that most people wouldn't think is possible. The extremely light cone and super-high magnetic force provides lightning quick response and it remains in control. It is used in speaker systems costing from $2500-$25000. It's cheaper if you build your own cabinet. What is not to like about a speaker like this?
Best to who? If everybody had the same ears we would all buy the same speakers. Go listen for yourself and come to your own conclusions. You can spend a pile of money and end up with something that sounds like crap. I think the better question here would be "Who has the better room" because if your room isn't right, the so called best speaker in the world will stink! One last thought---money does not have to buy better. Some of the speakers are like buying a fine wood hutch. But where did the money go? And if you believe reviewers--- well, I have some prime swampland here in the lowcountry you can buy. It has great bug and wildlife reviews!
Bigtee sums it up quite nicely. I've heard 6 big name speakers, all way over priced. So i hope we have less "best speaker" threads and more research on previous threads. It's all there, every speaker has been reviewed here on Audiogon. I will say that auditioning speakers locally can be a big problem, since most cities only have a handful of "hi-fi" shops, with limited lines. Oh, as everyone knows my vote goes to...kits. I should have mine up and running in about 1 month.
Best, who knows.
But I'll rank what I owned/had in house for you from the best down:
Alon Grand Exoticas (by a knockout!)
Sound Lab M-1s
Suspect the Kharmas are at least as good as the Trios,
and the Rockport Hyperions up there as well.
Trust your ears, listen with equipment you know intimately,
and be prepared to write big checks for incremental differences. Reviews mean little-why else would everything be class A if not to please advertisers?
Tyler Acoustics Taylo Reference Monitors or any of his Reference or Linnbrook models. Take my word for it, this speaker company is going places... I have owned over thrity pairs of speakers and his take the cake. If the company was public, I would invest without question.
Check it out www.tyleracoustics.com
Tyler uses Seas, Which i've been prearching here for the past 4 months, ever since i "discovered" the superioity of the Seas Excel drivers. There are many issues with the MTM design. And as well i can find many other offerings with Seas drivers for alot less money. (However some are made by German labs=import). I will say that Tyler uses superior xover components and that the cabinets are very nice, that may justify the price to some. There are 3 superior woofers: Seas Accuton Skaaning. So if you want "best" dynamics, make sure the cabinet houses one of these 3.