Sold Polk lsi15 now what?

I owned the Lsi15s and had a similar reaction. They did nothing wrong, quite a bit right but just didn't thrill me. Mine were replaced with Proac Response 1.5 which brought about the same reaction. Ended up pulling my trusty Meadowlark Kestrel Hot Rods from the closet and was immediately feeling the music. Smaller and less expensive than the Polks or Proacs but more fun to listen to.
I read in a thread just the other day someone pointing out that once you get used to a good time and phase coherent speaker it's hard to find satisfaction elsewhere. I agree with that.
In your price range I'd look for a pair of Vandersteen 2CE signatures or maybe a used Thiel model. Good luck with the search.

How about a used pair of Magnepan 1.6 for about 800 - 900 bucks.

I still have the Lsi15s but purchased the 1.7s. for a second system.

I listen mainly to jazz in its various forms.

If you have the room they are a significant improvement with exception of not being able to reach down in the bass region like the Lsi15s. It depends on the recorded bass content. About 90% or more of the time the 1.7s cover the recorded bass content.

For your musical tastes find a nice pair of Alons. I have seen V MKIIs go for $600-$1000. Fantastic on jazz and classic rock IMO.

Happy Listening.

PSB Image T65 (last year's model). Natural-sounding, room-energizing dispersion, very transparent midrange, and full, deep bass. They were $1200/pair new; now closeouts and used ones would be fairly new and should easily hit your budget.

What type of sound do you want. Use as many descriptors as apply. Listing that you like Jazz and classic rock doesn't tell me whether you like clean detailed sound or something a bit mellower. The Alons have the rich sort of full/big tone if BigKidz knows your preferences for some reason.