Which speakers have wide dispersion?

It sounds more natural - direct and reverbernat energy match. Sound is good in a much larger sweetspot. Sound is easy to listen too and relaxing as opposed to the headphone feeling you get with narrow dispersion speakers. You can enjoy the sound withouthaving to lock your head in a vice.

Speakers that follow this principle are many. Audiokinesis, Energy, Mirage, PSB, Merlin, Axiom, just to name a very few...it is the main reason that dome tweeters are so successful. It is one of the major challenges in a midrange - especially in a two way.

Many speakers do not - but to name them would cause unnecessary flames.

The Mirage Omnipolar and Omnisats have uniform room-filling dispersion, but with a forward-firing bias that improves imaging. The listening area is the sweet spot in the sense that if you are at a live performance sitting to the left of the stage, you still hear all the instruments and voices from the perspective where you're sitting. The Omniguide-based Mirages do the same thing. The center position is especially sweet, but the soundstage doesn't collapse when you sit outside the speaker pair. You still hear it as a soundstage.

I have a pair of Omnisat satellites and a pair of floor-standing OMD-15's. I also installed a sat/sub Omnisat-based system at my neighbor's living room. I've found that the Mirage speakers with the Omniguide mid/tweeter module are very easy to place for musically satisfying placement, but also reward more careful placement for better soundstage and imaging.

You will get good results even if you have to place the speakers close to the wall behind them, but you get better imaging and soundstage depth if you can bring them out 2-3 feet from the wall. The tonal balance assumes the "average" room with a mix of hard and soft surfaces, but you can definitely fine-tune the dispersion and treble energy by adjusting the ratio and locations of hard and soft surfaces.

I've gotten good results from both rectangular rooms with std. ceilings and open architecture living spaces with vaulted ceilings. Like I said, they're pretty accommodating of your listening area.

Dali speakers too.

Having been a fan and owner of various types of planar speakers for over 45 years, I can wholeheartedly agree. Conventional dynamic (box) speakers are the opposite, with the sound coming from a point source, albeit when done well can present a wide and deep sound-stage. Nonetheless, you need to be in or at least near the sweet spot or there is a great drop off in many critical aspects of the sound. For the last many years I have become more and more enamored by the large Sound Lab electrostatics. With these, there is not a bad seat in the house. Even in the next room and beyond, it is as if you are near the presence of live music, with full timbre, body and presence. Because the entire panel is a full range membrane/driver of considerable size, all of the air in the room is excited and this carries on. My wife doesn't much like the audiophile "sweet seat" experience, but she loves being in the near presence of the great music. Granted, the imaging is generally best at one particular point, but every other seating position is entirely enjoyable. So my vote is not really omnidirectional, but electrostatic planars.

Even though there are some very fine cone based systems out there, I would have a hard time going back to traditional speakers.