QUOTE(Solari @ Jun 10 2009, 12:59 PM)

I've never really been much into choral stuff but of late I've run into a few pieces that absolutely blew my socks off.
While it's short, Mozart's Requiem In D Minor K626 - Dies Irae is absolutely amazing, and I'm looking to find more powerful stuff like this (for my tastes, the darker the better), so throw your 2p in
If you are after 'dark' music then the following might suit:
Orchestral (some of which include choir)Tchaikovsky - Symphony no.6 'Pathetique'. (This is in my opinion one of the darkest pieces ever composed and it has one of the most powerful bassoon solos ever written. The subtitle 'pathetique' was added by Tchaikovsky's brother the day after the work's premier, and eight days before Tchaikosky's death.)
Benjamin Britten - Symphony for cello and orchestra.
Sibelius - Symphony no.4, 7 and Tapiola (the 3rd movement of the 4th Symphony has a hauntingly beautiful flute solo).
Vaughn Williams - Symphony no.7 'Antarctic' and Sea Symphony
Stravinsky - Symphony of Psalms, Symphony in C.
Bruch - Violin concerto.
ChoralMaurice Greene - Lord, let me know mine end.
Kenneth Leighton - Solus ad victimam
Vierne - Messe Solennelle (the organ parts are outstanding)
Duruffle - Requiem
Rutter - Requiem (I find some parts of this very moving, but there are a lot of people who hate it)