I've seen some amazing photos taken with the Noctilux, and others that just make me seasick with the swirling bokeh. Someone once memorably described the Noctilux bokeh as "ghostly lightbulbs." It will be interesting to see the results from the new f0.95 aspherical version.
From what I've read, one reason the Noctilux is so expensive is because it requires special glass that needs to cool over the course of 18 months. Anyhow, at $6k used, I won't be buying one any time soon either.