I had some Triangle Comete ES and absolutely loved them. I sold them to a friend and each time I visit him, I am shocked at how good they sound for $500. Very tube friendly in many ways. They aren't bright at all if your electronics are of good quality. But they don't have much bass authority. The Triangle Altea ES is another very good choice with extra bass and yet still efficient because it is a 2.5 way.
Totem would be similar to your Quads in terms of power requirement. Some Dynaudios have a nice impedence curve but they can be a little thick in the lower mids which doesn't work with certain tube amps.
All the Reference 3A are great options.
Also Amphion from Finland, like the Argon 2. It doesn't dip below 7 ohms and has fantastic reviews. They also have efficient small floorstanders.
Another option is the Coincident Triumph UHS from Canada. It only needs a few Watts to sound good.
Ditto the Omega speakers from Conneticut. I have been very curious about the SuperHemps which only need like 5W and are inexpensive for the quality of finish and sound you are getting. One of the best high efficiency deals going IMO. I used to have a pair of Grande 8 and still regret having sold them.
Arthur
