One of the more recent movements in the Classical music world is Minimalism. You can find a thorough introduction to the concept here, but my understanding of the basic idea is this:
The Western musical tradition is nothing more than the evolution of meaningless ornamentation – the best way to express musical ideas is a few at a time, and you should take the time to appreciate them.
I haven’t really listened to much of this music, but The Photographer is a fine example. Its composer is Philip Glass, probably the most well-known composer in this style. If you’ve seen The Illusionist, Secret Window, The Hours, or The Truman Show, you’ve heard his music (though these are mostly in Post-Minimalist or other styles).
What I find really interesting is that Trance music works on the same principle, though it hasn’t been as thoroughly defined or debated. There have been many recent offshoots of Trance that are more song-oriented (which kind of parallels the evolution of Post-Minimalism from Minimalism), but the original Trance that came into its own during the early-mid 90’s relied on the extended repetition of a few musical lines, which slowly evolved over the course of the song. Ishkur’s guide has plenty of examples.
