music recommendation

I've always liked choral music, but despite having an extensive music
collection, I've never owned any... can anyone recommend a good compilation
to introduce me to it?  Though I tend to like the kind with only voices, not
with big orchestra parts.  I also tend to like darker music, in general.  I
like both "mundane" and unusual harmonies, so anything that spans the gamut
would be good.  I've searched a little on Amazon but there are so many
choices.

thanks for any help!