My all-time favorite "chill-to" album, which is now in storage, sadly (I wasn't smart enough to retrieve it last time I went to Pennsylvania) was SONGS OF THE WEST by the Norman Luboff Choir. A choir singing songs like "I'm A Poor Lonesome Cowboy" and "Old Chisolm Trail." This album never failed to calm me down and cool me out whenever I came home from a too-long day. Soothing.
Others:
AQUELLA NOCHE by Tish Hinojosa is a lovely, atmospheric set of Mexican folk songs. Her version of "Estrellita" gets me every time.
THE PEACEFUL SIDE OF BILLY STRAYHORN is about the last thing you would have expected from Duke Ellington's right hand man-- an instrumental piano album with small trio and "jazz voices." It's an easy listening album with a jazz tint, and it works beautifully.
PIANO REFLECTIONS by Duke Ellington.
(Not an ad for the sponsors of this board, but both of those last two albums are on Capitol.)
JOHN COLTRANE AND JOHNNY HARTMAN, which, I hate to go along with the crowd, but has to be the all-time greatest jazz vocal album.
A trio of Frank Sinatra albums:
CLOSE TO YOU
MOONLIGHT SINATRA
FRANCIS ALBERT SINATRA AND ANTONIO CARLOS JOBIM or the follow-up, side one of SINATRA AND COMPANY, which was tracks that were tagged for a second Sinatra-Jobim collaboration. Funny how, right when Sinatra complained that "no one's writing songs for me anymore and I don't know what to do about it," along came Jobim.
(SINATRA SINGS FOR ONLY THE LONELY and NO ONE CARES are just a little too dark to chill out to sometimes)
A recent discovery:
VOICES IN LOVE by the Four Freshmen, which Brian Wilson called the greatest pop vocal album ever.
Also THE GENTLE SIDE OF JOHN COLTRANE is a compilation, but that's not ITS fault. Still a great album to chill out to.
The closest thing I can think of by the Beach Boys is FRIENDS, maybe, or side two of TODAY.
And speaking of album sides, side two of A1A by Jimmy Buffett is a lovely chill-to album...side two of George Harrison's LIVING IN THE MATERIAL WORLD is nice... SILVER AND GOLD by Neil Young is a nice one, although Neil admittedly is not the kind of person whose music you usually put on to RELAX.
CHET BAKER SINGS is a good one. Like Brian in his prime, a natural high sweet voice... and that HORN, too.
I'm sorry... did you only want me to list ONE??