So, in a characteristic display of childish impatience

, having decided that the
Mamiya C330(f) was the MF camera for me, I tracked a few on eBay and won one 5 minutes ago

.
It's the 'F' model with the (later) 'blue dot' 80mm f/2.8 lens. Although I really wanted a wider lens, I decided to just try using the lens that seems to come with all of these cameras (i.e. 80mm) and see how I like MF photography first. The 80mm is reckoned to be one of the sharpest of the bunch (and has the widest max aperture), so I should certainly get a feel for how good the image quality can be. Equally, if I discover (God forbid) that MF negs don't scan any better than 35mm negs on my scanner, then I'll probably just put it back on eBay and chalk it up to experience :shrug:.
So, I will let you all know in due course how things go with my new toy and will post any questions that I have in this part of the forum (this thread, even).
For now though, I really want to say a very big and very sincere
THANK YOU 
to all of the people who've offered their thoughts and advice on this subject. If I hadn't been part of this discussion, I have a feeling that I would have spent a lot more money on something that may not have been any better for me than the camera I chose.
For an inexpensive, interchangeable lens route into medium format photography then the Mamiya C330 are a great choice.
I had one many moons ago and they are very good. Heavier than the Rolleis and Yashimats but then you get the flexibility of changing lens. I agree with Jim above see one and handle one in the flesh first as they are taller than the more traditional square bodied machines and not as light as other TLRs.
Lens quality is very good and I think either take 46mm or 49mm filters so plenty around. They can be a little challenging when using graduated or polarising filters, but with a little though can be used.
A friend of mine still has and uses one and I might see if I can borrow it off him sometime soon.
http://www.btinternet.com/~g.a.patterson/mfaq/m_faq-contents.html
This site gives a fair bit of information about the whole Mamiya TLR range.
Hi Nick!
Thanks for the link and your comments

. As you can see, I went with the C330 after all. I'm planning to use it mounted on a tripod most of the time, so as long as it's not too heavy to carry (and at 1,700g it's even lighter than the D700 kir that I normally carry) then I don't mind. The RB67 model (at appx. 4kgs with one lens), was just the wrong side of that line for me :|.
They seem to be going for around £130-150 on the bay at the moment. Good choice I think for your requirements, I've been looking at them myself as the interchangeable lenses appeal to me.
Andy
Hi Andy!
I paid 158 quid, but that's fine with me if the image quality turns out to be as good as I'm hoping

. Crikey, £158 is less than I've spent on some of my old Nikkor manual focus primes and they're possibly not even as sharp as the Mamiya 80mm f/2.8

.
The extra (55mm) lens would be expensive though

. I may have to forget that idea.
I've got a C220 and really like it, it is bigger than the Yash's and Rollei's etc but if you're holding it at waist level then it's not really a problem, I've also recently acquired a C330 as well, it's substantially heavier the C220, it weighs in at 1.15kg and 1.4kg for the C330, that's without a lens attached, an 80mm f2.8 lens weighs 300g and a 65mm f3.5 is slightly heavier at 327g. So if you're going to carry it around all day without the benefit of a strap then it's akin to carrying a house brick around but then you cant get a decent photograph out of a house brick.
Well said that man

!
As I said, I plan to just carry it in a shoulder bag and only take it out to put it on a tripod every now and then. Usually, when I go out anywhere to do 'serious' photography, I have a (gripped) D700 with a 70-200mm f/2.8 VR lens and some metal-bodied manual focus primes too. The whole lot weighs well over 3.5kgs - this C330 is
half that!
Let's see how it all works out

.
Thanks again everyone! G'night.
Andy