Well i think "psy" projects never knew how to make good chilled stuff,
Some of my favorites:
-Future Sound of London-Lifeforms(masterpiece)
-Boards of Canada-Music Has the Right to Children
-Xingu Hill-Maps of the Impossible
-Beefcake-Drei
-Sasha-Airdrawndagger
-Aphex Twin-Selected Ambient Works 85-92
-Autechre-Incunabula
-Pan Sonic-Aaltopiiri