Listen Listen Listen
I must agree with davemcc, go listen to as many different speakers as you can. Audition as many as you can, and for as long as it takes.
We all have our favorite speakers. B&W, M&K, Definitive, RBS, or XYZPDQ. OK I threw that one in to see if you were paying attention. I have owned every one of the speakers above, and all have a special quality.
A couple of rules I live by.
1 Take the music you listen to, to the store to audition the speakers. This is what is going to be playing at your house. Although Acoustic Alchemy, or Diana Krall may sound great in the demo room, it that what you're going to listen to at home?
2. Take your time and listen as long as it takes. If the salesman/person/woman wants to hurry you along, leave immediately. They don't give a flying **** about you, they only want your money.
3. Don't listen to what the sales people think they sound like. What do you think they sound like? Do you get tired of listening to them quickly? Do you like what they sound like? Listen to them at the volume you usually listen to music/movies at.
4. Listen to them from many different angles. In the sweet spot, off axis right and left.
5. Make sure the amp/receiver they are using is comparable to what you have at home.
6. If you are buying these for mainly surround sound and movies, remember 80% of the movie comes out of that center channel speaker. DO NOT SKIMP HERE!!!!!!!.
But what ever you do, just listen. Listen. Listen. Take your time and Listen.