At the time one of my audio buddies bought a pair ofType A speakers, he had a large, by New York standards, studio apartment. Those 4-foot (1.2 meter)-tall speakers sounded great; they produced tight, well-defined bass, natural midrange and a sweet treble. A few years later he moved to a one-bedroom apartment, with a living room about half the size of his studio space, and the speakers' sound suffered. The bass was boomy and thick, and the stereo soundstage was closed-in and cramped by comparison with what he had before. In short, the speakers sounded completely different.
It wasn't just the new room's size that messed up the sound -- the old room had wood over beam floors and sheetrock walls, while the new room had a poured concrete floor and cinderblock walls, which adversely affected the room's acoustics.
We knew what the Type As were capable of, so we experimented with different speaker placement strategies, but never did manage to get the Snell Type As to sound as good as they did in the larger room. After a few years he gave up and bought a much smaller pair of speakers (Symdex Sigmas), and they produced much better sound than the Type As in that room.
The lesson here is that speakers only achieve their full potential in rooms with acoustics that complement the speakers. It's something of an oversimplification, but big speakers usually only sound best in large rooms, and small speakers in tiny rooms.
So if you're lucky enough to have a large house or apartment, don't skimp on speakers: look for large towers, with 8-inch (203mm) or larger woofers. Take the opposite course with small rooms, and go for bookshelf or tower speakers with 5-inch (127mm) or smaller woofers. For home theater applications, scale your subwoofer size to the room, and for huge rooms, or if you crave very loud, feel-the-room shake bass, use two or more subwoofers.
Rooms with lots of exposed windows, mirrors, hardwood or tiled floors will sound overly reverberant and harsh. Rooms with heavy drapes, thick carpets and overstuffed furniture will sound dead or muffled. Rooms with a mix of hard, reflective surfaces, and soft, absorbent surfaces usually sound best.
Speaker shoppers should try to arrange for a home audition to confirm the speakers will play well in their room. If that's not possible, ask the dealer to visit your home to make an educated guess. Or send pictures of the room to the dealer, and once they see the room they will have a much better idea about what might work best there.
The speaker/room "interface" can make or break the sound of your music or home theater system. Searching for the "best" speaker without taking the room into account is a risky proposition.