the big one: how do you choose speakers? By what features, data?

In home trial is important, but it's hard to compare with other speakers. The sound in an acoustically treated store room will not be the sound in your room. I am a firm believer in controlled HF dispersion to prevent early reflections. I also believe there is no substitute for room treatments. The LEDE theory has always worked for me, Live End behind Dead End to the front. Don't go by specifications, nobody has an anechoic chamber for a room. Most important trust your ears in your room. An audio chain is only as strong as it's weakest link. Matching components is important and there are a lot of factory direct places that allow 30 day in home trials.

I used to sell hi end audio and the mark up on speakers is insanely high. I myself have gone the factory direct route. A few years ago I was reading a TAS review of the Emerald Physics EP2.8’s and took a chance. I bought from Underwood Wally after talking to Walter Liederman (owner of EP) for a few hours on the phone and I'm glad I did. Sold my B&W 802D's and never looked back. The EP2.8's were less than 1/2 the price of the B&W's and are a much more lifelike sounding speaker IMO. Axiom's Audio M80's or M100's are great value, well made and sound better than most brand names in their price range. I think they still offer a 30 day in home trial too. I have also had the pleasure of listening to the Hsu CCB-8's with the Hsu ULS 15 MK2 subwoofer. They are too big to be called a bookshelf speaker and need stands, but that package is truly a giant killer and efficient enough to drive with a smaller amp or receiver because the subwoofer is self powered. Dr Hsu demonstrates it with a little 10 yr old Sony receiver and the sound is truly astounding and not just for the price, astounding period. These speakers all use some kind of directional control of the HF's. The Hsu and the EP's use concentric mounted tweeters inside the midrange driver which controls dispersion and early reflections that can smear the image. I believe Axiom also uses a directional lens tweeter to control dispersion. Go to these websites, find a speaker in the price range for your budget and read as many reviews as you can. See if you can connect with an owner for a listening session. Emerald Physics is just coming out with their new line, and according to Wally they will be an evolution, not a design change. These are of course just my opinions.

Nobody in this hobby was born an expert. You need to sample as many speakers and combinations as you can. I believe that a good speaker is good on any type of music. If it isn't then it is coloring or detracting from the sound. For me my number one priority is vocals. If familiar female vocals don't sound real to me I'm out right there. Some speakers do a wonderful job on everything but the lowest audible octave (20 Hz to 40 Hz). That usually is the most expensive to reproduce accurately and typically requires the addition of a sub-woofer. Anything lower than 20Hz is felt more than heard, but can add to realism. Piano is also a good test of a system. If you live in an apartment you may not want that lowest octave. Bass is the most likely to cause a standing wave which is dependent on your room measurements. A standing wave can double or half the bass output, and sometimes you just can't relocate the speakers to eliminate that effect. Bass traps and corner treatments of acoustic foam can transform a room. The speakers are only one link in the audio chain. Trust your ears!