Most detailed speakers in 1K range?

If you can find them, I'd highly recommend a pair of Proac Studio 150's. They were $2300 new and should cost about half that used, though they're rare. Any of the Studio series will give you most of that wonderful Proac sound for less money than the more well-known, and more expensive, Response series.

If you want to buy new speakers for $1000, and want a beautifully detailed speaker for listening to acoustic instruments, I strongly urge you to consider Richard Sequerra's Pyramid Met 7.7. I owned an earlier version of this speaker. They have superb resolution, accurate instrumental timbre, nearly holographic imaging, and do a terrific job of reproducing acoustic instruments. As mini-monitors, they lack the bottom octave, but I'm not sure you will miss it much. Sequerra sells his speakers directly, and the price is $990 plus shipping. The Pyramid 7.7 was reviewed by Sam Tellig in the July 2000 issue of Stereophile mag.

Without a doubt the Meadowlark Kestrel is a PRIME choice in your price range. A used pair of the 'Hot Rod' (biwire with enhanced rigidity) should run about 1K (new $1500) They're floorstanders so they don't need stands, and have adequate bass response (due to transmission-line loading) for most average-sized listening rooms. Give them a listen!