Most beautiful relaxing music or soundtrack you have ever listened to? Retro 50's, 60's and 70's music is welcome.
For example European music, Italian music, American, Classical music, R&B music, Rock music, etc.

Blade Runner by Vangelis.
I do not often listen soundtracks completely, sorry if it's the only one I'd mention.

Otherwise they are plenty of "ambient" sountrack, I'm not sure they are all worth mentioning.
Some stuff are dark, or sad, I'm not sure this is best to relax.
I remind I liked Pan's Labyrinth by Javier Navarrete.

I do not consider Rock as relaxing.

New age and easy listening are great. But I have to say Hollow by Matti Paalanen is soooo relaxing only four songs and the genre are ambient, instrumental, postrock, shoegaze, minimalism... try it if u like I try asking him for the flac version and was willing to pay too! HOLLOW (http://www.jamendo.com/en/list/a3615/hollow)

videogame music is what youre looking for.

True, thats always case though that or anime soundtracks

It's still pretty recent but the Tron soundtrack from Daftpunk is a pretty awesome listen.

....mother and child by edward shearmur.

human stain by rachel portman
secret garden by zbigniew preisner
unfaithful by Kaczmarek
winter guest by michael kamen
Comme les 5 doigts de la main by armand amar
away from her by jonathan goldsmith
fireflies in the garden by navarrete
beyond rangoon by zimmer (yes, zimmer)

others....

relaxing (for my taste) is one of my major criteria, as relaxing mostly is harmonic...

i would not at all be able to place those in time though, retro 60ties or anything. sorry.

not a retro track, but this music is what i listen to when i want to sleep, relax, bike around the city - Capa's last transmission. No other songs have trumped that so far for me.

Sunshine Soundtrack Capa's Last Transmission Home - YouTube (http://www.youtube.com/watch?v=FkOJeSn9J9Y)

I Always Find A Nice Bit Of Mozart Relaxing Or Medwyn Goodall's New Age Music (I'm Quite Partial To The 4 Medicine Woman Albums)

Uhh, let's see... Finding Nemo by Thomas Newman.

Danny Elfman - Ice Dance
Badly Drawn Boy - I love NYE

Pierre Van Dormael - Mr. Nobody

Max Richter - Perfect Sense

Rolfe Kent - Sideways

Philippe Rombi ~ Joyeux Noel
John Barry ~ Indecent Proposal
Wojciech Kilar ~ Portrait of a Lady

Relaxing music from the 40's and 50's is the kind of music I like most.

This Chrono Trigger OverClocked Remix cheers me up and i find it relaxing as well
https://www.youtube.com/watch?v=iSExeQUf4-8

For retro/synth-style music I'd say these three:

Artisan Loyalist - The Awakening (https://artisanloyalist.bandcamp.com/track/the-awakening)

Future Unlimited - Someone Like Me (https://soundcloud.com/future-unlimited/future-unlimited-animation)

Meet Me In Orbit - Enter the Night (https://soundcloud.com/meet-me-in-orbit/enter-the-night)