Delerium - Karma album
that reminded me of some big hit from the 90's - definitely a different group though, but I cant place them (yet)
Enigma does some similar stuff. I first heard them on that IBM commercial with the Native American chanting. I think the title is "return to innocence."
The hit on the Delerium album was Firefly.
I like stuff that has chanting or Gregorian Chant. I found a "shaman healing chant" the other day. It is like an hour long. Incredibly subtle harmonies from the background singers. Plus that hypnotic flute. Really cool.