Based on some recent posts regarding sound stage and imaging many Audiogon members have wildly different ideas when defining sound stage and imaging. I recommend you look into used open baffle speakers. I’ve owned a variety of speakers including Von Schweikert, ,Zu, Tannoy, Klipsch, Genelec, JBL and Snell. None of them come close to competing with open baffle.
You’ve got a large room which is great for a high efficiency open baffle speaker. You won’t need to worry about acoustic treatment but they do require space from the walls. Check out the reviews of the Lii audio speakers. You could build your own baffles and be very happy!
Sound Stage and Imaging
I love speakers who 'paint a big picture' (I am literally closing my eyes and trying to SEE a picture). Therefore I THINK I like to see IMAGING and BIG SOUND STAGE. And also like DYNAMICS.
Being frugal (just not willing to spent audiophile level money on it), I love to persuit 'bang for buck' solutions in general.
With above goals in mind for a speaker: what hits the marks in the low fi (audiphile scale) $2k (used or new) budget range. (I have 2 setups: one HUGE room, one 20x20).