Interesting discussion, and you (mypasswordis, sorry can't remember your real name) can articulate much more than I can regarding consonance/dissonance.
I heard the U of I Percussion Ensemble perform a Xenakis piece years ago for a PAS Iowa convention thing when I was in school. The hall must have matched Xenakis' design because I could have sworn I was hearing synthesizers (as in ELP), as in a "wow-wow" moving around the hall. All from acoustic drums placed in the balcony at strategic intervals around the hall.
Stockhausen: hehe, pretty much the wildest shit I've ever heard.
In music theory classes, where I heard the Stockhausen and other 12 tone pioneers, we did an analysis of Wagner, Parsifal (my screen name), Overture. From what I recall, 300 bars or so where you could kind of glimpse key(s), but couldn't nail it down. A lot of step-wise movement in the piece, moving from key to key, starts here, comes out there, but in between? Very "tonal" sounding piece of music as well.
Question: how much do alternate tonalities fuck with people who have perfect pitch (i.e., my mother among them)? I'm sure this is tied somewhat to the tonality system that they are accustomed to.
Add to that Baroque tunings, etc.