Best speaker value between $1800-$2100

Need some input on best value in speakers between $1800 to $2100. I have been out of the market for 3 years due to illness. I currently have a pair of Silverline Prelude II speakers which are above average. I am driving them with a Creek 5250SE Classic which is about 85RMS. I prefer a speaker with a narrow profile(like the Preludes) because the room is 12X15 with mostly hardwood floors and wall of window area. I also have some overstuffed furniture; but, overall the room is lively. I don't have a lot of flexibility in the room for speaker placement; I currently have the Preludes placed on the long axis---they sound somewhat louder on the right speaker. I use a pair 10ft of Analysis Oval 12 which may need to be replaced. All opinions and advice will be welcomed.
Vandersteen 2 sigs or used 3 sigs
There are plenty of speakers in that range that are more than worthy of a listen.Remember,what Joe or Sam or I like might not be your cup of tea.Try some out if you can.That being said,I bought a pair of Tyler Acoustics 7U's without hearing them and I could not be happier.Sometimes you just get lucky!!!!
My favorite sounding speaker in that price range is the ProAc 2.5, but it may be a difficult match for you because many people feel they need to be away from the walls more than some speakers. I however, used them about 12-18" from the walls and still loved them.
Used Helicon 400 with the ribbon tweeter combo.
Von Schwiekert VR4jr v1, Spendor s8e, s6e or s5e
I am assuming you want to replace the Silverlines with small towers. I suggest you check out these front ported models:

-Aperion Audio 6T (Internet direct),

-B&W 683 (big),

-Focal 816V,

-Monitor Audio Silver RX8 (new product), and

-Rega RS5.

Three other speakers I really like in this price range are the Epos M16i, B&W CM7 and Quad 22L (a bit boxier but very sweet), but these are rear ported and may require placement a bit further into the room, or muting of the port with a plug.
Are the Silverlines not good speakers? Maybe the Creek should be replaced instead?

I do not know but it seems the Creek is a bit old and I have always read good things about Silverlines.

Would help if you described what you're looking to improve over the Preludes. Some good recommendations above, so I'd add the Salk Songtowers that seem to get very nice reviews (and they can be had new in your price range) or maybe the Gallo Ref. 3.1 used. If you like the Preludes maybe a used pair of Sonatinas would be a nice improvement. Actually with a room of that size you might do better with monitors, which opens up possiblities like Usher Tiny Dancer, etc. Of course with no idea of your tastes or preferences this is just throwing darts in the dark. Best of luck.
Just saw a pair of Silverline SR17.5s for sale here at a little below your minimum price (so with stands you'd still be in the ballpark). Hard to imagine these wouldn't be a fairly significant step up in performance from your Preludes.
Allow a budget for some room treatments as with all tha glass any speaker will have problems.
I'm in a very similar situation to yours, and have tentatively settled on a pair of Ohm 1000s, which retail for $2000. Looks like they might be a good match for the Creek also.
I have tried several speakers with my Creek 5350SE and settled on Von Schweikerts. They work well together. You may not need even the VR-4JRs (which I own) since even the VR-2s would probably work well. I am currently using the VR-1 plus a small REL sub. The speakers disappear and I have a smooth flat FR from 30 Hz on up.
you know-- agree with the poster above that the Response 2.5 from Proac is a lovely thing-- owned a pair for several years. But prior to them I owned the 1.5's and felt them to actually have the more upfront present midrange of the two. The profile is also more slimline. The 1.5 worked better for me in my smaller (14 by 16 or so) room and was readily driven by all manner of amps. it wasnt till I got to my current Daedalus speakers that I felt I had arrived at a "better" speaker (with a somewhat more natural top end).
Soooo.... for a slimline look, easily driven and sexy to boot-- in that price range, what about a pair of used D15 Proacs? That's the upgraded version of the 1.5. You could also go with Totem Hawks or with a used pair of Reference 3A Veenas. All very musical sounding speakers. The Hawks would be a GREAT value used.
What is it about the Silverlines that you wish to improve upon? There are numerous high quality speakers that fit your aesthetic criteria, many of which have already been mentioned. With some additional information you may receive responses more narrowly tailored to your preferences. A "house sound," by definition, varies from manufacturer to manufacturer, so I think you would be well served to give us an idea of your goals and priorities.

Kind regards,
Hawks are nice but fussier about power. I might suggest the Totem Sttaf as more flexible and in this price range new.
Normally, I would say Magnepan (for example 1.6QR), but with a smaller room and with that amp (although I really love Creek's, they really don't like Maggies...). I doubt you could make them sound good due to room size.

Vandersteens are always a good choice, especially the 2CE Signatures. Easily within your price range, and much below if you look at used. Not too difficult to on the amp either.
What is it about your speakers that you don't like or want to change ? Are you married to your amp ? Maybe the Creek/Silverline synergy is not working .

If I remember correctly , Silverline has been voicing some of his later stuff with SS . I am not sure if the Prelude 2 is one of these or not .

You might try talking to them to get their recommendation on amplification . Could make a world of difference .

Good luck.