haunting/dark classical

Mozart - Piano Concerto #20 in D minor K.466
Brahms - A German Requiem Op.45
Tchaikovsky - Marche Slave Op.31
Liszt - Totentanz for piano and orchestra
Prokofiev - Scythian Suite Op.20
Mahler - Symphony #9
Shostakovich - String Quartet #8 Op.110

A good sampler. All of the compositions are "standard repertoire" and recordings are readily available.

Cheers.

I Second Gorecki Symphony #3
Try Also Tchaikovsky Symphony #6 and Shostakovich #7 & #8
Enjoy

I'm very fond of most of what's been recommended and applaud the others for their thoughtful responses. I would like to recommend a piece that won't qualify as Classical music in the usual sense but it is orchestral and most definitely describes what you're are looking for: the sound track of "The DaVinci Code." It's extremely dramatic and dark. The recording is wonderful, too, with unusually good dynamic range and low frequency reproduction.

Schubert's Unfinished Symphony #8 - Get the complete Symphonies box Frans Bruegen and the Age of Enlightment Symphony Orchestra. Mozart's final work - the Clarinet Concerto, he had alot of haunting/dark problems in his life when he wrote this work.

Haunting, dark,classical. Phillip Glass. Dracula, Low, and Heroes. Played by Kronos Quartet.