As a Leica-phile, I feel it is my duty to point out that the best thing about a leica, IMHO, is its ability to quietly, inconspicuously, and easily allow you to take a photo in just about any lighting situation. Which means that you will eventually want a fast lens. And the leica fast lenses are probably the best in existence(again, purely my opinion). The bottom line is that an f/4 lens on a leica is akin to putting tire chains on a Porsche.
Very good point!
"You miss 100% of the shots you don't take"...Wayne Gretzky