OK. I understand that you're talking about your experiences here. I also assume you mean to include only passive speakers in your comment, because, for instance, Vandersteen Quatros are not efficient and yet they would be excellent for the OP's room as the bass in so configurable that it would allow him/her to augment the bass. Low volume listening will sound great. Of course the Quatros are out of the price range here, but just making the point about this slightly inefficient speaker being more than adequate. And yes, there are ways to decouple it from the floor if people want to comment about the low-to-the ground ports.
However, I believe you need to state which inefficient speakers you refer to as well as the amplifier driving them in order to make the general statement you're making. I had J.A. Pulsars in a small room for instance. Not an efficient speaker by any means, but it sure sounded wonderful at low volumes with any of my amps. Again, theses speakers are out of the OP's price range but the principal doesn't change with price: some inefficient speakers can be wonderful in small rooms.