Most achingly-beautiful music

Agree with the adagio from Albinoni Oboe Concerto in D - truly haunting. Massenet's Meditation from Thais. The so-called 'Flower Duet' from Delibe's Laksme - ('Dome epais le jardin', or something like that)
On the more folk-jazz-pop front; Sandy Denny's 'Carnival' from the album 'Like an Old Fashioned Waltz';
Van Morrison's 'When the Heart is Open' from the 'Common One' album.

Roger that; Samba pa ti.

For something off the beaten path, but definitely in the achingly beautiful category, try the track 'Theme From Harry's Game' on Clannad's 'Past Present' album. It is a deeply melancholy, but soaringly melodic dirge, sung in Gaelic by Enya, before she was known as a one-name new- age solo act. A fitting lament for the Irish troubles, as portrayed in the excellent, little known British film: 'Harry's Game'.

Back to the classics; Song of India, Rimsky-Korsakoff, (lonely stevedore working on the Volga river in Russia pines for his homeland) and the penetrating (in a good way) violin solos from Scheherezade, 3rd and 4th movements, same composer.

As to Golfrok's nomination of Pat Metheny, allow me to specify his rendition of 'Ferry, Cross the Mersey' on the recently released 'One Quiet Night' Album.

For all you youngsters out there, that tune was originally a hit for Gerry and the Pacemakers on the first wave of the British Invasion - what would that be '64, '65? Had some of my first slow dances to that one.