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
I have listened to the NHT Super Zero, PSB alpha B1, Silverline Minuet, Paradigm mini Monotors. So far the Minuets and Mini Mononitors sound the best for me. The Minuets are smaller and have a very large sound. The Mini Monitors have this great 3 d sound. Hard to pick right now. My room is small 11x10 with a bed
Thanks for all your suggestions. Its hard to obtain some of the speakers used to audition. I want to try the ushers , Triangle, Rega RS1 and Dali Zensor 1.
After searching through all the mini monitors, I purchased the Silverline Minuet Supremes. For my surround sound minis bought the Monitor Audio 90s. A real sleeper that was purchased for $60 for the pair,new in the box.
Larger monitor bagains include the Quad 12L, Quad 11L, VS VR1, Usher 520 and Wharfedale 10.2.
ACI Sapphire III or Anniversary if you can find a good deal. I thought my old Sonus Faber Concertinos sounded good but the Sapphire III were much better.