I saw a Mamiya 6MF on the shelf today and couldn't help but play with it. Actually I would be happier with the first version (non multi-format) since I only want it for 6x6 shooting. But wow, what nice camera! But the body alone was about $600 and the 50mm lens they had in stock was $500! Obviously way, way out of my range. But if Santa came today and asked me what I want it would be either the Mamiya 6 with all three lenses or the Fuji GF670. I'm not sure which... the portability of the Fuji is definitely a plus but the lens options of the Mamiya are pretty sweet too.
For the time being I will convince my self to be completely satisfied with my Fuji GS645 and my very old but still usable Mamiya Six (bellows type circa 1955).