Confused with size of speaker to get when placed along long wall in large room

Thanks for the thoughtful replies.

Erik_squires:  I will certainly look into the AM Acoustics simulator.  Some of the walls and ceiling have alcoves, cutouts, and deep coving, so the amount of echo seems under control, but I think I am missing out on a certain amount of acoustic magic.  Right now I can’t tell how much is the room or the speakers.

curiousjim:  the space is a contemporary open floor plan.  I’m sort of resigned to the fact that I cannot get optimal sound in the space.  Since it is a common space for the family, minimal room treatment would be tolerated.

As for the Cornwalls, I am currently using a Leben cs600 to drive them.  I have used as little as a 1W LTA MicroZOLT amp to drive them satisfactory.  I will look into new amplifiers, once I settle on the speakers.

@djwong , my home sounds like a similar layout to yours at a slightly smaller scale. One way to (partially) remove the room from the equation is with a point source design. A more focused presentation in your sweet spot, but you may give up something when moving about the house. Maybe add Daniel Hertz, Tannoy, or Fyne Audio to your demo list.

Shooting from the hip here, but you may want to check out Larsen. 

https://www.larsenhifi.com/en/larsen9.htm

There are some very good recommendations already made here.  At your preferred listening levels it will be very hard for any pair of floorstanders to get you a smooth response and not sound thin.  I would strongly consider adding a pair of subwoofers.  This will really open up the list of speakers that will work in the space and maybe allow you to get a speaker that you love the sound of that otherwise wouldn't work.  Good luck and cheers.  

If you like the presence of Klipsch but want to move away from the horn-like nature of it, Vivid Audio speakers would be very good for your space. Models like the Kaya 45, Kaya 90, and anything in the Giya lineup all feature side-firing woofers annd ports and do not require much distance from the front walls. The designs of the speakers largely follow an organic transmission line, and the results are like the combination of the presence of a horn, the high frequency speed of electrostats, and the dynamic punch of a cone-centric speaker. They also cast a very wide dispersion, which will also work nicely for your wide room. 

I am a Vivid Audio and Perlisten dealer, and between the two, for your particular room, I would encourage you to look more into Vivid. 

Regardless, it may be worthwhile looking at a set of subwoofers or a swarm to better improve room response. Doing this allows you to worry less about the size of the speakers, and you could even get away with something smaller. In that case, Perlisten makes some of the best subs on the market. I personally use Vivid G1 Spirit and Perlisten D12s subwoofers in my room.

if you have any direct questions on any products across Vivid or Perlisten feel free to message me privately, or continue to ask on here and I’ll respond.