as ive stated to Josh again and again--Penderecki. i am currently listening to Utrenja, a track that was included on the soundtrack to "The Shining."
perhaps his greatest work lies in his Dies Irae. i never knew how many different ways one could strike a bow or their instrument in general. everything from crawling creatures to some super-sonic low end bass movements supplement a totally intimate experience with darkness and its little monsters.
George Crumb: Vox Balaenae (Voice of the Whale); and of course MAKROKOSMOS!
John Cage: all of his sonatas and interludes for prepared piano.