Being surrounded by fellow space nuts, I assume I'm not the only person here who's into the ambient genre. If I were to pick my three favourites it would be these albums, especially the first two:
Jonn Serrie - "And the Stars Go with You"
Global Communication "76-14"
Carbon Based Lifeforms "World of Sleepers"
Brian Eno's "Apollo"
Ashra's "New Age of the Earth"
It really pains me how neglected this genre is. I guess in part it's due to it having no practical application -- No particular setting at which it, and it solely, is suited, apart from relaxation, which is what most people associate it with. Oh well.