I've been seeing so much now about the M9 and learning about rangefinders...not necessarily a good thing for me, because I'm catching the M9 bug. If I take the plunge, I like the idea of picking one good lens; when using DSLR's I have always used a single lens for 95% of my shooting, and I prefer 24-70mm, or a bit longer. Obviously the zooms give a lot of flexibiloity. I like the 24 at the wide end. However, with the M9 I would expect to be choosing a prime. I would love to have a very high quality, fast lens 2.0 or faster. Opinions from those with experience using FF Leicas (digital or film) are sought.
So my question, "If you could have only one lens for your M9, which would you choose?" Would you choose the traditional 50mm "normal" lens, or go for a different focal length?
Also, what is the benefit from using newer "6-Bit, Updated for Digital" versions?