Best small, desktop speakers, $500 or under (new or used)

Someone earlier mentioned powered tannoys. Those are good and come in versions less than 500, and then you could sell your amp and have money left over. There are other great powered options as well. I currently have ATC and Omega monitors but have had many others such as ProAc (which are great), Tannoy etc. One hidden gem is the JVC UX 7000. I just bought another pair for my office. 

https://www.ebay.com/itm/254608934017

Another great option is the Linn Kan

https://www.ebay.com/itm/184310348338

@lancek Wow, those JVC speakers are $37, used!
As for Omega -- is there more than one Omega or is that just this company? https://omegaloudspeakers.com/

Omega makes good speakers but has terrible service .

@schubert Good to know. Everything on their product page says "sold out" and there is no notice about when things will be back in production. It would be hard to guess what the fate of that company is.

Honestly, my old DCMs give me 90% of what I think is awesome, snare, piano, vocals, and the 'wrong' stuff is modest enough not to bug me. My old Tukans were good for me at under $400/pair. Most ADSs I hear give me most of what I like. I'm sure the $1500 speaker can do it better, but maybe not. They give me more base, but the high end is too subdued. Or they soundstage is super big, but the sensitivity sucks for my 60 watt amp. ALways a trade off.