I'm edging towards buying a Panasonic four-thirds camera for everyday use - see
here. The Panasonic G1 looks good, and I see from the sales blurb that due to the cooperation between Leica and Panasonic you can get an adaptor to allow the use of old Leica 'M' and 'R' mount lenses (I think R are the old SLR lenses).
I don't know anything about Leica stuff. Would it be worth getting a used Leica lens for the Panasonic, or would it be better to stick with the custom-made lenses that Panasonic are bringing out? I would have thought that if the Panasonic are optimised for four-thirds, they would be better. But I don't really know.
example of used Leica
G1 camera