Mini Monitors under $500 used

I have a small room 10x10x8 that Im using as a den. Have a Nad 326bee and Marantz 6250 cd, what would you recommend for speakers? Detail, sound stage, and resolution are important to me.
thank you for answering
anyone pair the 326 with a pr of Paradigm mini monitors? wonder if the PSB speakers or Paradigm mate better.
also just read about Silver Minuet supreme and Harbeth (which are much more expensive).
Second the Usher S-520. It's a great speaker for the price and size.

In that price range, I'm also a fan of the PSB Stratus Mini's.

I believe nad and psb share same distribution and demo often...Fwiw...I was in a funky Thai restaurant with a amazing dj...I was so captivated by the sound I checked out the speakers...mid level psb...