I'll second The Moody Blues, at least up until around 1972. Any of the earlier Yes or Pink Floyd, King Crimson, early Genesis and Allman Brothers, too. Music is absolutely fantastic under the buzz of the psychedelic vibe. I also like the earlier 1960's tripping music: Beatles, Cream, Jefferson Airplane, Traffic, Jimi Hendrix and The Who. Even a lot of the pop was trippy in those days: Tommy James & The Shondells, Strawberry Alarm Clock, Iron Butterfly and the list just goes on... as does the beat.