High value, giant killer speakers?

Another vote for Magnepan LRS.
Right room / Right electronics = true high end sound / experience.

Speaker preference is so extremely subjective that any particular choice, even ultra-expensive models, might be horrible sounding to certain listeners.  Therefore, any "giant killer" candidate must be auditioned by the buyer before being considered.  I fear that these types of inquiries are a search for a rough consensus that is then used to make a choice without actually audition.

The mention of Magnepan speakers is good because one can easily find them for an audition.  I would add lower end Audio Note speakers as decent bargains that one should be able to find a dealer.  ProAcs may be harder, but, they too deserve mention.

There are a few quite decent sounding (to me anyway) speakers that are sold mostly by direct sales from the manufacturer.  They cannot easily be heard unless one can attend audio shows.  The Tekton Double Impacts impressed me for their decent sound at a quite reasonable price.  I also like the Rethm Bhaava speakers I heard at shows.  Much higher in price, but competitive with some really expensive speakers, are the back-loaded horns from Charney Audio.

If we are talking towers, Goldenear Tritons are unbelievable for the price and have better a soundstage image and dynamics than speakers four times the price. If we are going bookshelf, and really affordable, both ELAC and PSB make some killer options that are well under $1,000/pair. Now, I am a classical and jazz musician, and I listen for clarity and a big soundstage, but also full range dynamics. I want to hear the musician's breath, nice and soft, but clear, and then be blown out of my seat by crescendos in the music with no discomfort to my ears. There are other good speakers out there, but for my picky ears, and my money, these are the three I'd go to first.

I’m also a musician, and I was pleasantly surprised after all these decades as an audio freak and live sound mixer/system designer that Klipsch Heresy IIIs sound as good as they do. Until I bought a Dennis Had SEP amp which was initially used with either 91db or 93db speakers, I hadn’t thought much about higher efficiency (wasn’t satisfied with the sound of the 93db speakers and sold ’em, and eventually sold the 91db speakers, although they, Silverline Preludes, sounded great) as it hadn’t mattered much. Heresy IIIs filled the bill amazingly, and are very revealing of anything in front of them...cables, amps, sources, my Aunt Shirley (move please, I don’t wanna see your inappropriate dance moves)...Are these USA made fat little boxes worth more than the 1500 bucks I spent? (my "Capitol Records edition" pair listed for $2500)...yeah, maybe they are...but...meh...I hear far more "precious" rigs at shops around here and think many are excellent, but I think my rig sounds better all around...especially since it’s in my house.

2nd for the Fritz speakers, matched them with a tube amp and you wont be sorry....I'm only sorry I cant buy another pair for my living room (that is my wife's room :-)