Personally, I think that loudspeakers are a bit hard to define by measurements alone, primarily due to the large variability of the rooms they go in. Just one example. I used a pair of Revel F36s for a period of time while my Magnepans were being rebuilt. Initially the Revels were a bit bright and edgy sounding. This was due to their being 2 feet from the sidewalls and room I have them in being pretty lively. The Magnepans with close placement to sidewalls don't suffer from this issue, because they radiate much less to the sides than a monopole cone speaker. By treating the first reflection points (less than $200 in treatments from GIK acoustics) on the sidewalls, the speakers were transformed from bright and edgy to open, accurate, and smooth sounding. (Although those changes were nothing compared to me changing cables and using cable lifters: Just Kidding!!!)
Another issue is that some speakers are hard to measure. Dipolar speakers (Magnepans, Martin Logans, Sound Labs, etc.) cannot be accurately measured outside of a Anechoic chamber. Quasi anechoic measurements simply don't work as you get to the bass frequencies.
So all that said, speakers that measure well and most consider to sound good:
1) JBL, starting with the 305p which can be had for $149 a pair when on a deep sale.
2) Anything Revel.
3) Anything PSB.
4) Anything Paradigm.
5) Anything Ascend Acoustics.
6) Anything Salk Sound.
7) Anything GR Research (Carnegie Acoustics)
8) Anything Philharmonic Audio (Dennis is no longer making speakers, but has some DIY flat pack options he is working on).
In speakers that are hard to measure, Magnepans, starting with the $700 LRS. I own Magnepans, have used them for more than 25 years and love them. That said, they have caveats. 1) They need a lot of space. 2) They are inefficient and need a lot of power (smaller ones 200w/ch into 4ohms, larger 400w/ch) which needs to be factored into their price, as big amps cost more. 3) They have somewhat compressed dynamics compared to dynamic speakers (something that you never see measured). 4) They are limited in the bass (and I don't care what people say, I have 3.5's and subwoofers with a crossover help them immensely, giving deeper, tighter bass and a cleaner sound as the panels are relieved of deep bass duty).
Now next week, my opinion of Maggies may change. I am driving 500 miles each way this weekend to meet a person and purchase his Salk Song 3s, as I was able to demo a pair and was amazed at how clean they sounded.