The most haunting music you ever heard?

Richard Wagner's prelude and liebestod.

"Snowed In At Wheeler Street" from Kate Bush's latest album is a current release that has that quality.
Furtwangler's recording of Tchaikovsky's "Pathetique" symphony on DG.
"Gentle On My Mind" as recorded by John Hartford in "Natural To Be Gone" also comes to mind.

michael mantler/edward gorey "the hapless child"

Rx8man it sounds like a film score. Probably science fiction or supernatural. I realize that's a fairly large genre but I don't think it is classical or even jazz so that's what I am left with.

#1 at the blue whale from the original dark shadows series soundtrack.