I love how 90% of the responses in this thread are about the Leica! I did something like this about two years ago, except in my case it was a YashicaMat. I carried that thing around with me everywhere, shooting at least 3-4 rolls of HP5 a week. Looking at my contact sheets before, during, and after, the results are pretty startling. You can't help but learn if you just focus on one thing and do it really well. As soon as you add in all the extras like color, digital, zoom lenses, etc, you are missing the point. And no, shooting in B&W jpeg mode is not the same.