Best system used for $10,000 for classical music

DeVore Super 8s -- $4K
Naim 5i -- $2500
Naim Nait 5 Integrated - $1.5
Cables/Speaker Wire - $500 - $700
If need be the balence could be spent on an entry turntable (or sales tax)

Just an idea....John

Nothing beats electrostatics if you can place them properly (distance from front wall), so my suggestion would be

Quad 988 -- $4k
Pass Aleph 30 (or Aleph J) -- $1k
Modwright Modified Transporter -- $4k (new)
Cheap Oppo 980H CD player (for SACD and cases where the music isn't on the computer yet) -- $169
Computer for all the music in uncompressed format -- $1k

You can adjust your budget by stepping up in price to 2805s (around $6k) or down to 63s ($2k). The convenience of computer Audio is just too much to give up and the sound is very good too. This is pretty similar to what I use (Quad 2805 and iMac+Benchmark DAC1 as the computer solution). Many people use tubes amps with Quad (I have one too), but I prefer the Pass.

You didn't mention turntable so I assume that you don't have a lot of records. You should allocate some budget for that if this assumption is incorrect, but I don't think it is worthwhile to step into vinyl from scratch at this time.

Vandersteen 2Ce sigs---$1000 (used)
Raysonic 168 ---$2600 new ( get used if pos.)
AR LS-15---$1200 (used)
AQ Niagara 2 pair---$1500 (used)
AQ Volcano---$850 (used)
Channle Island D-200 monoblock amp---$2300 new (get used if pos.)
or AR D-200---$1000 (spend diff on VD David power cords)
4@$325---$1300 & worth it!!!
2 quads Amperex Orange label tubes---$200 (used)

total=$9650 for some sweet sound!

Sorry remove 1 power cord & $325!!!

You need to give a bit more info. Do you want digital or analog or both. Tubes or solid state (or hybrid). 2 Channel, surround, size of room?
The detail of your question will correspond closely to the quality of the answers you get. Spend some time and narrow it down.