IME Radiohead and Aphextwin go great together with Acid, they set a very intresting atmosphere and can help some very feeling strong, lucid like, feelings, arise. Proggresive rock too, shit like Pink Floyd, Yes, Jethro tull, even Genesis can take you to some cool paces, very diffrent then ambient/elctro stuff though.
Other Random suggestions: Miles Davis - Bitches Brew, Mr. Bungle - California, Tool - Lateralus, and some Zappa for some good, though not very introspective, fun time.