Low level listening

FWIW, I agree with Bartokfan that there is no contradition between successful low level and low sensitivity speakers. Being able to listen at low volume levels has always been a priority for me since I listen late at night after the rest of the family has gone to bed, and all the speakers I've ever owned have fallen into the low sensitivity category.

In my experience, the critical factors to success in low level listening have been resolution, consistency of tonal balance across the frequency range, and ability to resolve microdynamics. Speakers that have worked well for me for late night, low level listening have included: Celestion SL700s, Vandersteen 2Cs, Eidolons. None of these are high efficiency speakers, but all meet the three criteria I mentioned. I've also found that tube electronics help me in low level listening because of their greater resolving capability.
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Duke makes an excellent point that all of us should pay attention to:

Personally I place a high priority on low-level articulation even if the speaker is going to be played at high volume levels, because there will still be lots of low-level detail going on. And in my experience a speaker that still sounds good at very low volume levels is less likely to become fatiguing over a long listening session, so I encourage listening at very low volume levels as part of a thorough audition when you're speaker shopping.