A lot of good suggestions flying blind. As far as the immediately preceding, at least he didnt leave a link. (I hesitated to mention my Harbeth HL-P3's which you might be able to talk me out of for something more than your budget if I decide to get larger speakers for that room. They're small, and my favorites in the mini-size).
Problem is if you dont specify new or used, then there are about 100 different choices. A new speaker under $500 list may not satisfy you where a $1200 speaker selling for $500 would.
All of the above are good suggestions, the Krix and the Linn I think are the best (IMO).
A couple of other suggestions: (1) a used or demo pair of Totem Mites, amazing tiny speakers with high end sound, something I wouldnt say about the PSB's and NHT's Ive heard, and (2) if you want new, see if you can audition some of the $300 list 5 inch woofer speakers like KEF Cresta 2's, Monitor Audio Bronze 2's, Tannoy MX2's, and my favorite among these, the Acoustic Energy Aegis One's. I think you'll be surprised by the quality of the sound from these very inexpensive speakers.
