If I like Gorecki'S Symphony 3 I'll like.....?

Nothing quite as somber but equally beautiful moody vocals;

Natalie Dessay Vocalizes on EMI Classics

and there are a few excellent tracks here;

Tapestry - Come into my garden on Telarc.

Enjoy.

Mahler Symphonies 2,3,4 or 8.

Valentin Silvestrov. Check him out on youtube- "Silent Songs". "Metamusik; Postludium"

Alan Hovhaness