Photo credit: K. Praslowicz
Leica cameras have always been proclaimed as some of the quietest cameras around, making them suitable for street photography where stealth is preferred. Leaf shutter 35mm cameras can be quieter, but among focal plane shutter cameras I do love the Leica's cloth shutter with their "snick" sound instead of the metallic "clank" of other cameras.
If you hold a Leica in your hands for the first time without any other cameras for reference, you might wonder what's the fuss about, for the shutter is plainly audible as you click away. Test it against a couple of cameras, and you will realize why people don't hear you with a Leica.
Photographer K. Praslowicz recorded the clicks of several cameras at one location with similar shutter speed, to give you an idea of the relative loudness of each camera. Check out his article here!
http://www.kpraslowicz.com/2007/12/16/the-quiet-camera/