"Absolute best" used speaker for $8-10K

I gotta second the Zu Definitions. AND, that's a big AND--you can have them for $9k in a choice of colors brand spanking new with a 60 day money back guarantee. Can't beat that with a stick. Check out their website as well as the archives....fasten your seatbelt: this list will get very long and very different. It's the nature of your question...good luck. Let us know what your decide on...peace, warren :)

You could definitely get the Dunlavy SC-Vs for that or perhaps the SC-VIs. They are huge speakers, but really have no sonic equal at this price point( but it does require enough room space to let them breath).

There are a few but B&W Nautilus 800N is a steal under $10K preowned. One of the world's best speakers out there, regardless of price. I even prefer the B&W Nautilus 800N over the brand new 800D. Just a matter of taste at this level between the two. No weakness in this speaker. Just need an equal high quality system to receive full potential.

only one's you can audition

Avantgarde Duos again - just spend some time setting them up properly - when done well, they're great, when done poorly, you'll wonder why you wasted 10k!!