Best speaker between 15K-35K

Room size will play a major role. I have not listened to all the speakers on Holz list but I can second the WP 7's with the appropriate sub. I have not heard them with the Whow sub but I have with the Watchdog sub. It would be a match in audio heaven with your ARC pre.

If possible, audition a pair of Soundlabs A1. They are an amazing speaker regardless of whether one uses tubes or SS gear.

Tvad, a sub is not necessary with the W/P 7's. The bass is lightening fast, smooth, deep, and as tonally accurate as any speaker I have ever listened to. The addition of a properly set up sub, the watchdog in my case, appears to augment the entire range of sound, not only the bass. It is a subtle difference but one that can be heard and felt. It is not necessarily more bottom end, but the sub captures the ambient bass line in singers voices, strings, instruments, etc. for a fuller smoother all around presentation. It is not that the W/P 7 in particular is missing anything, any speaker system will benefit from this. I auditioned this set up in the same room with the mega dollar X-1's and I preferred the WP 7, watchdog combo. The X1's needed a larger room to sound their best.

..i would also include the piega c-40s' and their little brother c-10 ltds.i have heard the majority of the speakers mentioned so far and think the piegas' are superior....but that's just to my ears. if you are indeed going to listen to all the speakers you are interested in you owe it to yourself to find a dealer and listen to these great speakers.