Bookshelf speakers for $500ish

@Timrhu, thanks for the link, but I couldn't view- it said I didn't have permission to view the page.

I'm guessing you have to be a member there to view ads. The ad is for a pair of "mint" RS1s in piano black finish for $440 all in. I'm tempted every time I check classifieds at that site even though I have too many speakers already. It's just that I recall auditioning a pair of the Rega speakers a few years ago and was impressed.
Good luck with your search.

You mentioned two speakers you were considering. I am not familiar with the KEFs however do own the B&K 685s, which I use in a second system. I heard then in a dealership placed on a shelf against a wall and they sounded very good driven by a Rotel 1520 integrated amp. I bought them on AG used with the idea that should I wish to change, I could sell them at little loss. The 685s do show up used here on occasion for ~$350. I also heard the Rega RS1 and also liked them. However temporal distance and environmental differences prevent me from making any comparative statements.

Do you have a dealer for the speakers you are considering who would let you audition at home?

@Mesch: I'm not sure if they offer home audition, it's worth checking into. Their price is $800 for the Rega- double the cost of a used Minuet that I could sell for a little loss, as you mentioned. I'd be interested to hear from anyone who's compared those two (RS1 and Minuet).

I'd try powered studio monitors. I have Equator D5s now and they are quite good, although with 5" woofers the bass is light. You also avoid the cost of a power amp. I have not heard any passive speakers in that price range that are as good as the Equators. In fact, I had Mackie MR1s actives (300 pr) that sounded quite a bit better than my BW 805 Matrix speakers to my ears. Bye, bye, B&W.

You can find used Mackies all over the place.

The Supreme Pluses add more "punch and snap" and are better suited for Jazz.

The RS1s add more "realism and clarity" and are better suited for classical/full scale orchestra.

I really enjoy the piano/string notes coming out of the Supreme Pluses on a small scale like duos, trios, and quartets but it gets a little congested with a full scale orchestra ensemble.

Keep in mind that both are rear ported so you would have to see if they would work in your room.

Good luck.