Well, it's always a matter of personal preference, but where's Bubble Puppy,
"Hot Smoke and Sassafras," or Strawberry Alarm Clock, "Rainy Day Mushroom
Pillow," or just about anything by Terry Riley? If you're interested, do a
search on Riley. He did a series of "All Night Concerts" during the '60's
that were pretty far out there. His "A Rainbow in Curved Air" is still one
of my favorite ambient pieces.
Enjoy the Trip,
Lulu : )
http://www.digitaldreamdoor.com/pages/best_albumspsych.html
I'm surprised Iron Butterfly didn't make the list.