recommend entry-level high-efficiency loudspeakers

Used living voice auditorium (new price = 1500). they are amazing for the price

Coincident Triumph,Parts Express/Dayton Reference MTM or the original Gallo Nucleus series two ball affair.The first two have 92db efficiency,the gallos are crossoverless at 89db.

Most Paradigm's are fairly efficent. I had Studio 40 v.2's and they were 91dB @ 8ohm. Horns are extremely efficent.

Good Luck

There are many products from Klipsch that meet your HE and economic criteria: Heresy, Forte, Cornwell. Easily available and easy to resell.

Have been using Klipsch La Scala's for the past 18 months, and they are amazing with SET amps. With 104dB efficiency, they'll play on minimal power. You can pick up a pair for around $1000. So you can easily find something within your price range. We have a $5K CDP and $6K amps we've been using with them. They are that good, in my opinion. So good, in fact, that we moved up to the Klipschorn.

Another excellent option is to contact bcrites (Bob is his first name) via eBay or the Klipsch forum. For under $1K, you can have his speaker called the CornScala, which includes the entire package: mids/highs of the La Scala, with bass down to 30Hz. He builds a custom crossover for it. A friend is running these with a system that runs over $15K. His maple veneer option is only $150-200 above the price of MDF. Lots of great options out there.
Best of luck,
Howard