Low volume-level speakers
beercan:
I recently created a system for my living room where the goal was to have a system that sounded especially good at low volume levels. I think you are already headed in an appropriate direction by specifying tube amplification. I believe that it is the synergy between the speakers and the amplification that makes for a viable low-volume setup.
I found that the combination of a low-power tube integrated (Antique Sound Labs AQ 1005 DT - which is a 300B SET amp putting out 9 wpc) plus a pair of single-driver full range speakers from Omega Speakers (actually, I got a pair of Hoyt-Benford Type 1 speakers which seem to be in the process of being phased out by Louis) to work extremely well. I chose the Hoyt-Benford speakers after a discussion with Louis (the Omega Speakers maker) about the size of the room that I was dealing with and my desire to run at low volume levels. I think that the Omega line has numerous models that, deepening on your budget and room characteristics, would be great for your purposes. I should also point out that the full range single-driver speakers generate a great soundstage compared to conventional speakers because the music has a single point source for each channel and the resulting "sweet spot" is much larger.
As I was trying to work out this system, I also purchased an Audio Space Galaxy 34 (32 wpc but 16 wpc in triode mode) and a pair of Nola Boxers (thanks again, Mark) which are very efficient. These four components were tried out in various combinations before the Antique Sound Labs/Hoyt-Bedford combination was settled upon as the best solution for our living room. I put the Galaxy 34 and the Boxers in a near-field setup in my home office and am very happy with that system too 8^).
Anyway, classical music, especially chamber music that my wife loves and acoustic jazz which is my weakness both sound great in our living room. My office system is not too shabby either...
Good luck with your search.
Mike