The best way to buy speakers on-line is to first get a baseline of what type of material you like to listen to. Go out and listen to some speakers and make a note of your observations and then record what they are made out of. Only then will you be able to know what speaker to buy.
You can listen to bookshelf types to determine this. Then you can make a qualified decision online.
Material is by far the most determining factor to your ears. A site that I’m seeing developed with the weighted index based on material is InwallReviews.com. In essence, that site is saying to look at the material vs. the price paid to get a great value in a speaker.
Three specific recommendations that I would offer for the question: “What speaker to buy” are here:
For inwall application for home theater, I am comparing Phoenix Gold ATC6, Infinity CS60R, Polk RC60i, and am looking at a Yamaha set. It is very difficult to measure, which would you recommend? Knowing that you may not handle all of these brands, are they comparable?