Leica's bokeh resembles gaussian blur and are tack sharp wide open (even more remarkable is how compact and light they are). The Leica Noctilux 50mm f/1.0 is phenomenal. First of all it's aspherical so you don't get spherical aberration when used wide open. And the stuff in focus is tack sharp wide open; meaning it can be used wide open, which is the whole point of an f/1 lens.
But of course, theres no such thing as a free lunch and such phenomenal quality comes with a phenomenal price tag as well.