The best speaker you ever heard?

Yes, I couldn't buy them when I had kids in college. Come to think about that I had the QLSs while they were still in public schools. I think I paid $3000 for them.

Rebuilt quad 63's with a triode tube amp

For many years I owned Crosby modified 63's with two pairs of Entec LF 40 subs. The sound was in many ways as good as it gets, particularly with respect to low level detail and dynamics at the soft end of the scale. Sadly, the speakers did have some limitations, dynamuc range at the loud end of the spectrum, bass extension without a sub, top end extension and most importantly reliability. Still one of my favorites. Note that Richard Lees is currently modifying the newer Quads and says that they surpass the 63's.

Revel ultima salon
Proac response D100
Quad 2905

stuck between the three for top contenders that I have heard.

Rockport Arrakis in a purposely built and tuned room mated with all Gryphon electronics (Mirage and Colosseum) is the best setup I've ever heard. I just can't imagine anything better, only different. The Clearaudio Statement turntable might have helped too.