Mapman,
Most of the high efficiency speakers I really like tend to NOT have as their forte the ability to play really loud. Rather, they tend to sound great when playing at lower volume. This includes some truly gigantic systems.
While not the same design, but the same designer, I much prefer the low-powered First Watt amps (I've had the J2 in my system for two weeks, I heard a friends S.I.T. amp) over any of the Pass Lab amps I've heard.
My very favorite amps are a pushpull tube amp running 252 meshplate tubes and a custom-built 35 watt OTL amp. The amps I own include a 6.5 watt Audio Note Kageki (parallel SET 2a3) and a custom-built pushpull 5.5 watt amp (249 output tubes). I like both amps more than any of the high-powered solid state amps I've heard (I like high-powered tube amps even less than most solid state amps).
But, I do think you have a good point about some new designs. When price is a consideration, some of the reasonably priced Class D amps are decent sounding (I like Bel Canto). These days, almost none of the better solid state designs are unpleasant sounding, they just seem a little dull and not as engaging as low-powered tube amps when playing at reasonable volume levels (higher volume is needed to make the music come alive with most solid state).