High value, giant killer speakers?

   Did that twice accompanied by great dissatisfaction once in the home. Not very well schooled on the giant killer thing. The venerable speaker system that I wanted was and still is fairly priced which is subjectively expensive. 
   As luck would have it an original owner pair popped up on the local Craig's List in Portola Valley priced to sell quickly by a very well healed young stock optioned millennial noid with a new baby. His cup runneth over right into my Land Cruiser. 

Save up, get what you want used and stay off that merry-go-round. 
   
 

Emerald Physics have won numerous awards and are very reasonably priced

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.