Are you going to print from film, or digitally scan
Are you going to print from film, or digitally scan
If you are planning to go digital from the negs or transparencies, the Wide angle is not really an issue. Both Photoshop CS3 and Photoshop Elements have excellent panoramic stitching capabilities.
I am inclined toward the manual (rangefinder) focus of the GS645S over the single focal length GA645W. I use autofocus, but have always bypassed the single focal length GA series in favor of the GA645Zi which has an excellent reliability record and a zoom from 55mm to 90mm (admittedly a fairly short range, but zoom nonetheless)
I also personally tend to think of wide angle more in the framework of close but wide subject matter rather than wide angle for landscape. Perhaps that's because I am using normal focal length (scanned to digital) and putting two images together in post processing.
In any event, the Fuji G series camera's are notoriously sharp and reliable after the first folding model caused Fuji to tighten up on their quality. I've had a number of the GS645S and very good performance from all of them. I have never had the GA645, because of my preference for the Zi, but heard fairly good reports on the GA640W.