I have been using the 645 for the past year and a half and have had three bodies so far. I might suggest that you look at the Super instead of the 1000s. I don't think it will be too much more, and it has interchangable backs along with better metering prisms available. It is also of a more modern construction, which of course means some plastic, in case you are averse to that kind of thing. I think your chances are a bit better since it will be a newer camera. I find the interchangable backs to be very useful if you are shooting something where you want to switch films quickly.
My lenses are the 45mm, 80mm, 150mm and 210mm. I don't use the 210 all that much any more with what I do and the 45 seems to get the most use. If you buy a 45mm, make sure that you get the S or N models, the older C models are a 77mm thread for filters, as if 67 isn't bad enough...
Also, if you plan to do much hand held work, get a grip or motor drive for the camera, they are kind of hard (for me at least) to get a good grip on without.