If you're going to say "cue the choir", then...
I've been meaning to get Hayden's Mass in Time of War for some time now after hearing it performed by a local chorale (at least by the time I next run a game). The nice thing about classical pieces for some of these is that they start so slow and quiet that your players may not even notice you've queued it up. Then just as they're getting into the meat of the action the
Carmina Burana (sp?) is an obvious classic - even more so if you can score a copy of the illegally-licenses-then-withdrawn techno version. Sadly, I had a copy on tape and have lost it since.
For a Japanese-warrior-culture themed, any of the Kodo albums work well. Massive pounding drums - what more do you need?
I like all of these since they do not have vocals which I find distracting, and are not terribly modern to pull people out of character.
On a tangent: when all the blood as been spilled and the survivors stand over the devastated field: Moby's "God moving over the face of the waters." There's a reason why it is so perfect as the final piece in the movie "Heat", where Pacino stands over De Nero as he dies.... We used it as the wrap music for a high-energy climactic finale of a LARP game (werewolf) and it was perfect for cooling things back down and mourning the dead.
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