If you can afford it, I agree with QG on the later models. I have a 503CX, which the 503CW that QG mentioned replaced. They're very similar, but the newer one has a different mirror setup (the 'gliding mirror') that makes it work better with very long lenses, if that's important to you.
I used to have one of the old 500C cameras, made in 1964, and it was worn badly, though it actually worked well. I like my newer Hasselblad better though, it feels like it will last my lifetime. Another thing, if you don't mind the extra cost, try to get CF series lenses, not the older C series. The C series are generally good optically (A couple of the wideangles improved optically in the CF series, but the normal and tele lenses were usually the same optical formula). The thing I don't like about the older ones is ergonomics. The thinner focusing rings of the C series lenses are harder to use and the aperture/shutter speed setting system is maddening. The aperture and shutter speed rings are locked together on the older lenses, and you have to push out on the aperture ring to disconnect it from the shutter ring. The lock is designed so you can set exposure then move up and down through the aperture/shutter range without changing the basic exposure set. I hate it, its a damned pain to work with. The CF series are unlocked by default and can be interlocked by pushing a button. I like that much better.
If you do like Wideangles, I know from experience that the CF-FLE version of the 50mm Distagon is a heck of a lot sharper (especially near the edges) than the C and CF (non-FLE) versions of the lens (C and CF non FLE versions are the same optical formula, the CF-FLE version is different).
