"what sounds best" is what you like. I have listened to a boat load of speakers. From Wilsons, to Sonus to Dynaudio, Josephs, Paradigm, etc, etc.
I have settled on a few for my tastes. My tastes run on lively, in the room performers, good sound stage and correct timbre. If I can feel bass, that’s enough for me as I like it articulated and w punch w/o bloat.
I’ve heard your amp. Your amp is kind of "just there" for me. Nothing spectacular. I am not into "beautiful" sounding as much as accurate so no "rounding off" for me. So with all that said I can recommend two speakers: For dead on "truth"...Verity. For a combination of truth with just a wee bit coloration to sweeten things up just a tad but still remains very flat..Proac monitors.
If you have a clue with what I like and it parallels your tastes, it’s a starting point.