I agree with @yogiboy, Harbeth's wouldn't be on my list for a low wattage tube amp. Another story if you were considering a 35wpc+ PP amp.
The Audio Notes are great speakers but they are not for everyone. I love them but some guys feel that they sound "dark."
You haven't described your room so it's hard to recommend. IMO, set amps and good horn speakers enjoy a magical symmetry. Certainly there is a whole line of new and vintage Klipsch Heritage, starting with the Heresy and on up. I'm partial to vintage JBL monitors featuring CD horns, but that's me.
Another way to go would be "full range" single driver speakers. I've owned Omegas and Coherent Audio from Canada. Both can sound wonderful and can be mated to subwoofers if you feel that you needed more low end punch.