I originally wrote a message comparing my experience with the Fuji GA645 and the Contax G1 (not having used a Leica in quite a while), but I realize that's not really what this should be about.
I use the Fuji because it does what I want it to do and it makes me happy to use it, not because of any inherent technical superiority. If the Leica fits your personal style, or if you have a desire for a Leica that no other system is going to meet, then buy the Leica. We can all put up arguments all day long about how system X is better than system Y, but in the end it's what will make you happy that's truly important.
When I read your original message the thought that crossed my mind was, "He wants a Leica." There's absolutely nothing wrong with that. And you don't need any technical justification to buy one. Ultimately, the thing that matters the most is the person behind the camera, not the camera itself. If you're using a camera that you like, you'll be more likely to use it and that will raise your chances of taking a great photograph more than any MTF chart ever will.
Best of luck to you.