Hmm, I was thinking that "trance" was something that would get you into some sort of meditative mood. Something that would not make you "aware" of its existence. Something very techno or dominating would prevent you from thinking freely. I listen to TD, Vangelis (and, God help me, "New Age") because the music becomes a critical background to my thought processes... not the focus. I think that if you are aware of the music after five minutes, then it is not "trance", it's just good ol' music.