Best speakers to buy for around $1,500

If you can stretch just a little there is a used pair of Tekton Pendragons for sale here that would really do justice to the music you tend to play. Or Tekton Enzo new with a 30-day in home trial I think. Whole lotta speaker for the money. Best of luck.

Given my own personal priorities, I'd almost certainly go with Magnepan MMGs ($600) and a pair of SVS SB 1000 sealed 12" subwoofers ($950). That's a true full-range system of crazy high SQ potential. You'll have to do some work to optimize integration, but -once dialed in - this one is a killer.

NB: I use a similar set-up with Rythmik subs and Audyssey to optimize integration. If you use only digital sources, I think this is an amazingly cost-effective solution. If you use analog sources, the ADC to DAC may be an issue for you.

Kef ls50

I would consider a bargain on rega rs5, as they are being discontinued. You probably can get them fro $1200 or less new, and they sound incredible low-midrange to treble, no one can argue on that. Bass goes low to 40, the quality is arguably good. I own them.
Magnepan .7 is another great choice, so is Vandersteen 1C (I have owned them). If you look at Focal, even at half the price, they are still ugly and hot in the treble, with no bass... never a bargain.

Another thought, if the Tekton Pendragon or Enzo are too large the Lore S is within your budget new. Last, and surprised this one hasn't come up yet, is the Monitor Audio Silver 6. Nice review in GoodSound. I think all the Tektons I mentioned and the Silver 6es would all be a big step up in refinement and provide you a much more audiophile-level experience overall while maintaining or surpassing the dynamics and slam you currently may have or want. Not a lot of speakers can do that (at least well anyway) at your price point IME. Again, best of luck.