Speakers least affected by room acoustics

To the original poster:
* floor standing, or bookshelfs on a stand and how high is the tweeter/HF driver off the floor
* how close are they to any other room boundaries
* is there a big screen TV between them (audio/video system?)
* is it a high ceiling, or vaulted one and if vaulted, are the speakers under the low, or high side
* dome tweeter, or full-range driver (size of sweet spot)
* is your seating position at, or away from a wall/window...and how far back
* how wide are the speakers apart
* is there a window behind your head
* is your carpet Berber, or thicker...or is it wood floors
* is your listening spot a fully upholstered chair and if you scratch your fingernails on it, is it noisy

The point, is that everything makes a difference. Without lifting a finger for any room mods, moving the speakers further into the room -- closer to you -- and using a spacing of no more than 8', tweeter center to center, will help. Toeing them in so you're directly on axis with the tweeter will also lessen the echo effect. The more you're in the direct soundfield (the nearfield as some have mentioned), the less you're affected by the echo. Notice I said you and not your speakers. Do a bit of research on HRTF and you'll understand why.

So we have HRTF, room impulse and frequency response, potential phase shift of a signal from the electronics and a persnicketty wife. Better pick up a pair of cans. :-D

The problem with most speakers is not always the drivers, ie a 10" woofer or whatever. The problem is usually a result of the cabinet resonance and what frequency it resonates at. High mass speakers have a low resonance point. Bad for your room, sounds good in car stereos especially if you are in the car next to you at a stop light. The whole car resonates becoming a huge speaker. Lighter and or smaller speakers have less and higher frequency resonance, which is much easier to blunt. 

Try a pair of the stand-mounted Elusive Unicorn Monitor MkII, with the newly-improved graphene-treated driver screws.

Whichever speaker you choose you will be compromised. Sound is just air waves bouncing around a room, and if you have a sub-optimal room, no speaker will fix that - just change the dynamics of how/where the waves move and thus what you hear. Have a look around this web site http://www.acoustics.salford.ac.uk. I built a custom audio room to their ratios - magically previously missing bass notes appeared everywhere - sorry, that doesn't help you.

If you like your speakers, I'd spend money on room treatments, or if you're digital, maybe try using a DSP to digitally correct the room, but unsure how it would go with echo issues. Upgrade the ceiling and put some nice panels like these in http://www.decortech.co.nz/wp-content/uploads/stCuths-project-bottom-sideimageV.jpg. or nice rugs on the floor.

The speakers that are absolutely the least affected by room acoystics are Bose 901's, if you can stand the sound at all. I can't.