High Efficiency Speakers Your top 3 or more

Audiokinesis Jazz Modules
Tonian Labs TL-D1
Cain & Cain Abbeys

I own the first two pairs, would love to own a pair of the third someday.

The Tonian TL-D1 is an interesting design. Think of it as a single driver wannabe, but with super tweeter and very simple crossover. I had been wanting to try these for 4 years (up until recently they listed for $1750) and found a great deal on a used pair here. Unless you pay extra, the finish is basic and will easily show some flaws, but the sound is extremely fast and transparent. They go down to the low 40's, and placement is flexible as you can tune the bass via the adjustable bass port. The cabinet is lightweight and has very thin walls (think acoustic guitar, violin, or similar instrument body) using the reverberations to voice the speaker.

Duke and Tony make great speakers (the new Audiokinesis Prism is interesting too for $2500), but take some opposite approaches in design. I don't think the TL-D1's have the timbre of the Jazz Modules, nor the punch, but they play a lot bigger than their size and are slightly more balanced tonally. In many ways they remind me of my old Spendor's but more neutral.

The Tonian TL-D1 that everyone considers a bargain, have a frequency response of 42Hz-40KHz. Limited bass response."

Yes the specs indicate that and I would say they are accurate. I would also say that with proper placement and adjustment of the bass port, the bass sounded like that produced by my Spendor 1/2e. Something I can easily live with.

Prior to buying my Audiokinesis speakers I looked hard a Dru Zuids and Audio Note AN/E. Logically, I always thought the Audionote would be a logical progression of my love for the Spendor sound, but with deeper bass. I will own a pair someday, but not yet.

I consider the Tonian TL-D1's a poor man's AN/E in some respects. However, you can get an AN/E kit and if you're handy put it together for around $3k. Now that would be something.