Easy to drive, outstandingly natural sound from 40-50 Hz up.....AN-E, O/96, others?

I like AN-E's that you mentioned and recommendations for the Spendor SP100.  I don't know what price range you are looking at, so as a broad mention of speakers that will probably work well with 50 watts, the following brands are worth looking into: 
1. Tekton (I heard their $3,000 model at a show and it sounded quite good.
2. Charney Audio--I've heard a $13,000 and a $17,000 model (same speaker with different full range driver) and both were VERY good, particularly the $17,000 model with the AER 3 driver).  
3. Rethm Bhaava--this is a $3,000 speaker with a wide range driver and a built-in powered subwoofer that sounds great for the price.
4. ProAc--I like a number of models in their lineup.  Although not that high in efficiency, their speakers sound quite good with modest power--must be easy to drive.  I particularly like the big D48R floorstander and the D2 stand-mounted speaker.
5. DeVore Gibbon X--perhaps not as low-power friendly as the O 96 Orangutans, but I heard them with a 30-watt Luxman integrated and the combination sounded quite good.

Good luck in your search.

wolf, out of curiosity, have you tried your Heresys on a stand to bring them up closer to ear level. I'm tempted to try them but the floor placement won't work for me. Thx.

Kalili...I tried them on stands as that seemed like a good idea, but they sound better on the floor with their original their little tilt back stands. I now have them 3 feet from the front wall pointed straight out with no tow-in, about 6 feet apart (measured from the center of the speakers), and 9 feet from my fat head. Great "holographic" or "realistic" or "psychedelic" or something sound, as it's like the musicians are right there in my listening space attempting eye contact and mumbling things about me...hey...they're watching my every move...gotta get out...