It's usually complete silence or natural sounds for me, but ambient also can do the trick, like Steve Roach, Robert Rich, Biosphere, The Orb, Namlook and all the other FAX fellows. But that's only when I want to go deep.
For the mystical Efteling-like experiences I listen to Philip Glass (Glassworks in particular), that man is a musical genius. I can also imagine that many would find it a wrong choice.
Some soundtracks work really well too, A Clockwork Orange for example sets me in the right mood for creative conversations and productivity (painting and drawing). Akira awakes the demons, if you want to invite those. Cowboy Bebop can be fun to listen to, and I mustn't forget to mention Paprika.
Furthermore, The Residents can be weird and entertaining if you're into it, lately I tune in to Limbic Frequencies on iTunes to discover a lot of good artists I never heard of.
I'm not going to mention Aphex, Plaid, Autechre, Ceephax, Shpongle and that sort of stuff (oops, I already did), It can be fun to hear in a trip, but it's all getting old imo, or it's just me getting old
Music can set you in the right mood, and sound(waves)/vibrations can trigger many spectacular hallucinations and visions, like the sound of drumming, Tibetan consonance scales (whatever they're called in English), rattles, and the didgeridoo. It's amazing what it can do, Mike!
:wink: