If you're keeping the Fuji 670, you could go with a 645 fuji to give you the choice of formats and lenses. The fuji 645zi doesn't have much of a zoom, but if you look on the zoom as just an added bonus, the rest of the package is probably way less than a pentax, and is a perfect street shooters camera (AE, AF, zoom, motordrive - even an onboard flash).

Ian