First let me engage in some internet partisan vitriol, feel free to skip this since it's not of any real substance: Best Buy Isn't. No highs, no lows, it must be a bose. Steelseries, the speaker so bad they refuse to publish their THD. Audiophile Quality(tm): If any of it were true then James Randi would owe someone a million dollars.
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Ok now that I've got that out of my system the meat of my post is that speakers should be only part of your system, and that without good sources and components your stuff will still sound bad (or at least not as good). Speaking just of speakers though you should look for things like good warranty support, good objectively verifiable statistics (thd, parts quality, frequency response etc), and specifically look for speakers which LACK anything even so much as hinting at anything remotely associated with "audiophile" anything.
That last one is easily as important as the first two since with audio equipment there's an enormous Emperors New Clothes thing going on. A lot of the worst equipment out there makes the biggest claims of superiority, usually accompanied by claims which are physically impossible or nonsensical. Actual quality hardware will generally cost a LOT less than "audiophile" anything, and rather than make nonsense but impressive sounding claims will simply list objectively verifiable indicators of quality, things like THD and impedance which can be measured.
If you want a crash course in what to avoid, basically anything remotely resembling what
These Guys say about cables. You'll hear a lot of similar stuff about speakers but with the names changed around a bit. I really would love to be joking or making a big deal out of nothing, but unfortunately I'm not.