I've just worked through the six CDs again, and was struck by just how fabulous her voice was. That bell-like purity, the ability to float it, and the ability to "belt" when the song required. On Amazon I've briefly sampled a number of the other chanteuses mentioned in this thread, and so far haven't found anyone else who comes close to her in terms of the timbre / strength / purity of the voice. Surprisingly, perhaps Alison Kraus, when she's in a less strongly country-inflected mode, would be my top pick so far.
So my question is: who comes close to sounding something like EC?