Aside from Brian Eno and Aphex Twin, what are some of your favorite ambient music albums?

I'm interested in finding more ambient music that is not strictly found noise, but has some element of musicality to it. I know that might be a controversial statement, but I'm looking for stuff along the lines of Eno's Music for Airports--something that clearly has a theme and relies moreso on atmospheric playing than it does on randomness.

Any recommendations?