The soundtrack to the game Riven was composed and produced by Robyn Miller using a Korg Trinity, Yamaha VL-1 and Opcode's Studiovision on an Apple Macintosh. It is available on CD.
Although it is a soundtrack, it is, in my opinion, overlooked as a wonderful ambient album in its own right. The tracks flow together a lot more coherently than most other ambient albums' tracks do, for a start.
The VL-1 provides very real sounding instruments giving the album an otherworldly feel, while the Trinity helps it sound more polished, modern and well produced.
Overall the album (apart from track one, which is just a sound effect lasting a few seconds and shouldn't really be on the album in my opinion) gives you a wonderful feeling that you're submerged in a beautiful world just beyond any other human's reach. If you've played the game it will remind you of the islands, and if you haven't, it is probably just as beautiful sounding.
Out of all the albums I own a copy of, this is the one I listen to the most while having a relaxing bath or giving or receiving a massage. The only other songs that come close are tracks one and three of Aphex Twin's Selected Ambient Works II, which won't last anywhere near as long.
I'd definitely recommend this to relax to.