The brightest lens available for any interchangeable lens camera system today, the Leica 50mm f/0.95 Noctilux-M works with any Leica M-mount camera and provides a field of view equivalent to a 67mm lens in the 35mm format when used upon the M8/M8.2 digital rangefinder.  Noctilux redefines the limits of available-light handheld shooting, and for some it is really a reason unto itself to shoot with the Leica M system.  There's no lens on earth quite like it, and it is a shame for the pack of brands making SLR cameras that the Leica M system's mount depth is so thin at ~28mm, because it prohibits use of this special optic on other brands of cameras (Panasonic's DMW-MA2M adapter allows use upon Micro Four Thirds System Cameras).

The Noctilux-M 50mm f/0.95 has made great strides over its well-known predecessor, the Noctilux-M 50mm f/1.  It was able to create 11% more light gathering capacity without lowering the peak central resolution.  Perhaps 11% doesn't sound like much to you, but when you're talking about an 11% improvement upon an already-amazing f/1.0 aperture it becomes quite substantial.

The Noctilux-M f/0.95 is born to shoot at absurdly large apertures of f/1.4 and brighter.  Don't buy the Noctilux for normal use; choose it instead because it can allow you to make pictures other lenses, no matter the camera behind them, could never achieve.  Together with the M8's excellent high-ISO abilities you can do things like capture an image of someone's face only lit by a tiny candle or cigarette's ember.  If you can see it, you can shoot it.

Add a neutral density filter and try shooting at f/0.95 in bright daylight; imagine beach snaps where backgrounds are completely unrecognized washes of sky/water blue and sandy white blobs.  It is almost like the feeling of a dream.  With the Noctilux's unique capacity, you could capture a full-length picture of your friend in Times Square and perhaps not even be able to tell that they were in that immediately-recognized setting.

The Noctilux has a floating rear lens group, which aims to provide higher performance at closer focus ranges.  Leica's also decreased vignetting with the Noctilux-even at f/0.95 with the M8 you'll only have 1.5 stops of light loss in the image corners.  Coding on the rear lens barrel will communicate to the M8/8.2 the particulars of the lens.