Most achingly-beautiful music

Brahms 4th Symphony (second movement); Rachmaninoff's 2nd Symphony (second movement); Grieg's The Last Spring; Mahler's 5th Symphony (adagietto); a lot of Tchaikovsky; Nat King Cole singing Stardust; and the nicest symphony ever composed--Dvorak's No. 8 in G Major. I've heard many renditions, but the finest (not necessarily in order) are by Kertesz, Kubelik, and Talich.

To Tubegroover: You are right on the Rach. 2nd---it's the third movement adagio (shame on me!) And while I'm here, may I also cite Dvorak's String Serenade, op. 22, and the lesser known Suk Serenade, op.6 .