I was happily surprised to see some of my favorite music listed above. I thought Audiogon was a bunch of dry, anal, academics. :) I'm gonna repeat (reinforce) one or two of the earlier posts, and add some new ones. Format is 'Band - Album(s)':
Can: Future Days, Tago Mago, Ege Bamyasi. Excellent production, psychedelic-fusion from the late sixties - early seventies. Start with Future Days! Available in remastered SACD!
Naked City (John Zorn): Grand Guignol, Heretic, Absinthe, Leng Tch'e. Be warned, this can be hard, intense 'noise' at times. Again, excellent production.
Autechre: Quaristice, LP5, Tri-Repetae, Draft 7.30. Electronica gone a bit wonky; nothing is quite right, which is precisely why its so right.
Stravinsky: The Firebird, Rite of Spring. They still freak ME out.
George Crumb: Madrigals, Makrokosmos III. Hard to describe. (Messiean on acid?)
Would love to see more suggestions on here. I am noting down all the ones I do not know. Thank you David99!