I like Philip Glass when I'm in the mood for some primitive repetition (that is a compliment, don't get me wrong). He was a surprisingly good opera composer by minimalist standards (Einstein on the Beach beats John Adams' Nixon in China any day), at least when he used to be on good form before the mid 1980's when he sold out.
Listen to Steve Reich or Terry Riley if you like Glass or American minimalism though. Both wrote superior instrumental music in my opinion.