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

Listen to monitors at an audio show. You will know when you hear it. Audio memory is short so back-to-back comparisons help. 

@ct10 If one has $8900, yes :)

I think there is a lot of great value around 3 and 7K  

If cost is a constraint, i would go with the competence level of the speaker engineer. It takes very competent engineering to offer something good at affordable prices. On the other hand, it is much easier to make expensive speakers that sound good. The latter doesn't take too much genius.

On that note, Andrew Jones (Elac, Mofi) Danny Richie (GR Research),  etc are names that come to mind. Lately, very reputable brands with serious engineering aptitude like Yamaha, Technics, etc are releasing hifi speakers at relatively affordable prices, i.e.,  under the 10k price bracket at least. I would go with those. 

If cost is no object, TAD, high end JBL, etc come to mind.

Andrew Jones Was with TAD before Elac. Perhaps best speaker engineer.  

decide on budget, shop used, read reviews, consider measurements. One of the most neglected things is matching the speaker size to room size.