What used speaker would you buy with $20,000-$35,000 and why?

MD, sometimes it matters.  Just depends as there are sweet spots in lines that make a ton of sense.  Then when you are able to properly mate these, that's when you get a value.   I've heard plenty of one driver systems over the years. That was the first thing that stood out to me about the Vandersteen line.  They sound like a single source speaker.  Very few do this for ME.  I am very sensitive to distorted highs and coherency.  That's why I've yet to hear sub systems that I truly love and would want to live with.  Balance is too important to music for me.  If it's not balanced, then I keep thinking while listening.  Takes away the fun for me.  Most of the lines I"ve liked in the past and present are first order cross over, true time and phase aligned.  The only built in subs I've liked are the Vandersteens since he's found a way for my main amp to keep it's 'sound' even on Richards subs/amp.  It's also nice to be able to tune the bass for the room I'm playing it in.  That's always the hard part, getting deep, tuneful bass AND loading the room properly.  I personally feel the Quatro is the best value in his line.  As I said, I'll be selling my Treo's to get the Quatro.  His speakers sound great on zero feedback SS amps and sound even better with tube gear if you want to run tubes.  Sorry to go on and on, but I"m listening now and have been for hours.  Just realized I need to head down to eat, lol.  Keep us posted on your search.  This is fun. Thanks 

NAB I think it would help to state your listening preferences, preferred system size and room size. I even think the desired volume is a factor as some systems can truly sound alive even at whisper levels, while other need to be full tilt to get that effect. Conversely, the latest ML Neolith and CLX I have heard as shows sounded wonderful quiet but soon fell apart at higher levels.

You’re In a great position to be able to afford SOTA speakers (used) Thanks to the obsessive nature of this hobby.

I do love soundlabs U1’s but they could be too large visually for your space. RAidho has always sounded fantastic to me. I have yet to hear Magicos latest offerings. Personally I am enjoying a smaller scale system that to me ear sounds like real music does- TAD CR1’s (used to sell them but no longer) and extended them on the high and low ends of the spectrum. I have had a singer friend sing along with tracks and it was amazing how close the recorded was to live (maybe this is an easier feat than I am thinking- has anyone else tried this? ). I rarely come back from audio shows feeling I have heard something better. But then again I don’t often listen to large scale orchestral recordings, which might be better on another system. (I’m mainly Into acoustic rock and jazz).

Another option is IRS V’s and have them rebuilt As Paul from PS audio has done. IF you’re in Colorado you could hear them. I would love to get out there someday to listen to that system and custom built room.

Hope you let us know what you eventually choose.

A broken ankle and a ruptured Achilles tendon have slowed this project to a crawl (no pun intended). So it may be awhile. I do know that I have to go to a few conventions and certain stores in Atlanta. We will see what develops out of this. Thank for all the advice folks. The room/components interaction is indeed significant. I haven't had any opportunity to listen to Vandersteen or various Planar speakers. Both deserve an audition. 

Thanks to all who have responded.  My man-shed (acoustic shed) may be the first item on the agenda!

You have all given me food for thought!

Can't go wrong as Atlanta has some great dealers.  Vandersteen has a top dealer there and they know the products well as long as others.  You should also check out the Maggies and KEF's while there.  All three are so totally different, but musical.  Hang in there and get better.

In an earlier post above, I voted for Avalon speakers on the used market. I want to amend that... I still love my Avalons, but I may have been extremely lucky in terms of the synergy between the Eidolon model I have and the Ayon amplifier I have. 

My point here is: Match the speakers to the amp ...or the other way around. Match the speaker cables to the amp, more so than to the speakers...