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

When I bought my last set of speakers, I looked at the speakers that the maker of my amplifier used at the hifi shows. With the lac of shops in my area, it seemed a good way to go.

I think the two biggest things are your room and your actual listening habits.

Your room, and what you are willing or not willing to do to improve it matter a great deal.

Next, how exactly do you listen? Be honest! If you listen at low volume while working or doing other things, you should optimize and buy for that. Don’t go out looking for speakers that play the loudest and have the most rumble inducing bass if that’s not how you are going to use it. It’s like buying a car for shopping that you test on the race track.

Next, listen for a long time.  Lots of speakers are made to excite you in the first 5 minutes.  Few stand the test of just vanishing and letting you feel music for hours.

I think @jchiappinelli pretty much nailed it. I could digress on #2, but overall it's a sound (pardon the pun) approach. 

@jchiappinelli 

I am puzzled about #2. I always read here: speaker x is good for Jazz or Classical. Then someone else says: a good speaker plays ALL types of music well

also "sound decision" :)