I was going to say if you had hasselblad H or V then you could just get the mount switched (about 3k I think) and get a different mount adapter for your cambo (I believe they sell those right) which would prob be cheaper then going into a new system. I believe all the AFD's will work with your back (correct me if I am wrong) but know that the AFDiii will since many people keep those as backups to their 645DF since they take the same lenses and backs and AFDiii's go for fairly cheap.
All the Mamiya lenses are relatively cheap second hand in great condition on the whole. I have recently started purchasing M645 N glass like the excellent 150mm f/2.8N MF and 80mm f/1.9N as well as the 55mm and 150mm 3.5 N lenses. They are built amazingly well metal constructor, and what I could see with my IQ180 in basic testing I think that they may out preform their AF equivalents. Certainly with the Mamiya lenses there is a large amount of sample variation, I would say more so with the older AF lenses (I don't know if you can check by serial number but I am sure you can). There are some people who have bought multiple examples and tested them (since they are inexpensive and move fast enough that you can do this without taking too much of a loss) like Jack did over at Getdpi here:
http://forum.getdpi.com/forum/lens-accessory-reviews/15710-mamiya-lens-overview.html - It seems like the zoom lenses seem to have some more sample variation but that just my impression from reading, in my experience my examples have been pretty good and i have always been happy, I used most of them on film and now on digital and have not compared them to other examples but have always been pleased with the results. If you are going to want to manual focus rather then use AF, I think the MF N lenses (which are later, although I believe many are repackaged or evolutions of the earlier C lenses). They are well built and feel great, and purpose built for manual focus, and I have not tested enough but believe that they may out preform the AF lenses which again could just be related to sample variation for my lenses, but we shall see.
As medium cool says, the APO's are amazing, some consider the 150mm f/2.8 to be in this series but I have never gotten a straight answer about that. I absolutely love my recently acquired 300mm f/2.8 APO but this is still one of the lenses which sells at a premium. I think the 55mm f/2.8N may be one of the sharpest lenses I have seen. and you can't forget the 50mm f/4 if you are going to want tilt shift and not willing to pay the premium for the Schneider. Also as he says the 75-150mm is the newest zoom and probably the best as he says, this is the one I have not used, but I can say that at least my 105-210mm f/4.5 ULD is great, and and I expect its largely because of the great glass in it.
Always heard a lot of good things about the RB / RZ and they each have their own qualities which are looked at in-depth all over the place. They are certainly inexpensive along with all of their lenses, even compared to the Mamiya AFD's and lenses. I would certainly consider this as an economic option, especially if the automation isn't a big deal which it seems like its not for you. Lots of great lenses to choose from, many focal lengths.