This totally reinforces what I Learned from years of seeing people buy/install typical audiophile speakers in more ambitous(at least in intent) home theater setups!
Most everyone here is suggesting some sort of typical "highend" audiophile passive speakers from the mainstream for their HT systems. And especially in this guy's situation, THIS IS QUITE THE OPPOSITE OF WHAT WORKS BEST!...sorry people.
All the potential clarity, detail, neuances, soundstaging, imaging, dynamics, focus, and coherency will be lost to the low ceiling interaction using those speakers you're mostly recommending! Not only that, but dynamics will mostly be limited,inherent in typical audiphile speakers. (if you doubt, compare to ultra high efficiency pro audio, horn, and even active speakers!).
I personally think you'd do much better, all things being equal, if you chose some more (high end sounding if you wish) DEDICATED HOME THEATER SPEAKERS! And, like the guy who recommended the Active ATC speakers(althogh that design wouldn't work as well, and would have the same acoustical challenges as the other "tweeter over mid/woofer" design's mentioned above), chosing much higher efficiency designs like actives will give you WAY BETTER dynamics and slam!
Also, every other aspect will be greatly improved sonically.
Keep in mind however, you still either need some serious acoustical attention to your room/ceiling especially, or you should stay away from typical "open tweeter mounted above midwoofer designs", and stay towards either "Dappolito", Horn loaded, or some other more "focused architecture designs" for speakers!
Basically, you need to somehow ensure you hear more dirrect sound vs, reflected sound from the mains in relation to the boundary reflections for good sound potential and foundation. In this room, you neglect that, and you're sonics will pay dearly!...and you can expect sonic mediocrity.
If you are after high end refinement, and still want an effective high end full blown ambitious Home theater speaker effectively, Systems Design Group in Redondo Beach/Torrance California makes a high end studio dubing grade ACTIVE audiophile speaker line called "AVLAR". These are active custom driver speakers that are high sensitivity and high efficiency, and pump out tremendous dynamics and power! They are very coherent, detailed, clear, refined, and audiophile grade in every way, yet utilize THE ACTIVE DESIGN for much much better dynamics and power handling/output, more like what you could expect from large commercial audio and pro audio applications!
Basically, dynamic are in another league!...alot like what you get from high end designs from Avantgarde horn speakers! (yet without the sever off axis listening limitations. Anyway, they're worth looking into.
Otherwise, I like Active speakers in the high end such as these for tremendous cinematic high end results, which are unsurpased!
If you chose to go more "main line speaker companies", I'd suggest considering likes of Infinity Prelude MTS's, NHT VT3's, and or other speaker systems with "built in active/powerd subwoofers" for efficiency! And/Or strongly consdier big (maybe custom, with 1000 watt amps) powered subs. Getting at least the bass woofers active is a necessity anyway.
Basically, what youre typical high end misses is the heart, soul, power, coherence, involvment, brut force, dynamics, and effectiveness for full blown dedicated HT experiences in a large difficult setting like what you have. You need to chose wisely, and avoid the typical pitfalls. (if you doubt, simply read '98-2001 issues of "home theater architect" in SGTHT magazine, and find out why that guy spent $300k on a system that sucked!!!!, and what it took to fix it!)
If you must go typical "passive speakers", consider the more controlled focused designs, use SERIOUS BASS MANAGEMENT, and get as close as you can to the speakers, and or do heavy acoustical treatment(wisely)
