DuaneB:
I really need to replicate myself first to get a grasp of half the things I would like to do.This could be very interesting but take a year or two of my life
Does anyone have any experience of the learning curve ?
Well, here's my experience for what it's worth. In the spring of this year Makerbot stopped producing their smaller 3D printer, the Thing-o-Matic, to focus on the Replicator. So they were selling their unassembled remaining kits for a discount of hundreds of US dollars (basically for a little less than half of the current price of the Replicator). I decided to get a Thing-o-Matic kit. Even though it came to me in a complete kit with well written documentation available online, it took me a couple of two-day weekends and a few evenings after work to get it assembled and running. Mind you, that's without any major problems and only a couple of instances of backtracking that didn't cost much more than an hour each. Once it was running the control software was fairly easy to use.
The Repraps brought up earlier in the thread are smaller, have less electronics to wire-up, and don’t have cases to put together. So they’ll probably be somewhat quicker to assemble, but be prepared to invest a significant amount of free time before you can use them.
Of course if you want to make your own designs you'll probably need CAD software of some kind (as opposed to just downloading STL files made by other people). If you're not already familiar with either paper drafting or CAD there can be a significant learning curve. Although the interfaces and other aspects can differ quite a bit, once you get the fundamentals it usually isn't a big hassle to go from one particular CAD program to another. There some decent free programs as well as a few commercial packages ~100 USD that would be more than adequate. For personal use, I have ViaCAD Pro v8 (I splurged a bit, it actually cost ~250 USD but they have a 100 USD version too) as well as DesignCAD 3D Max 20 (picked the latter one up during a clearance sale for ~39 USD) either series would be a good investment if you are serious about using them. I don’t have that much experience with free CAD software, but there seem to be some decent options currently available.