02-03-09: Mags5000That's why you need to honestly examine how you *will* use the system, rather than how you might use it under ideal conditions. In my case, with an open architecture living area and various kids and dogs moving throughout the area, I chose Mirage omnidirectional speakers. They're compact, sensitive, and turn your entire living space into a general sweet spot. They exhibit very even timbre, tonality, and stable stereo image whether you're sitting, standing, walking about, or off to one side. Yet if you sit in the sweet spot, you do get more detail and soundstage.
The answers given above are good advice indeed. But, be honest with the type of listening you will be doing. I spent a huge amount of money on a dedicated room, high dollar system, room treatments, and was rewarded with a great listening experience. I now listen to that system about 10% of the time. In my pool (table) room I have a less expensive system that is in use the vast majority of the time. I have friends over, we eat, drink and party rather than sit in the sweet spot.
Many speakers only sound right if your ears are at the tweeters' height and you're no more than 15 deg. off axis. That type of speaker is fine for nearfield monitoring, but for a more sociable setup, omnidirectional--or at least very wide dispersion--speakers rule.