Thanks Ill look into the canon but I am kinda leaning towards a Leica lens.
Weeeelllll, if you need a Leica, you gotta have a Leica. if so, the Summicrons mentioned above are a good choice.
If you're open to being diverted....
M3 equals the 1950s by origin. Many think the Canon and Nikon 50s beat the Leicas of the same decade. if you don't mind spending much, the Canon 50/1.8 has a great rep and is readily available. The Canon 50/1.4 is very nice, optimized for mid apertures and mid distances, the Nikon 50/1.4 optimized for wide open, close focus shooting.
The ZM Planar and M Hexanon also look very good at the modern, contrasty end. Haven't followed their prices, however.
Best part, you can probably buy any one of those, shoot it yourself; sell it w/o much, if any, loss if you end up not liking it.
Suggestion -- listen to all the advice, think about what type of shooting you do, narrow it down to 3 options, more or less, and then go to flickr and look at pictures taken w. those lenses. Not scientific, but some characteristics come through.