Poser 4 - Metacreations version with at least one Curious Labs patch (there might be more but I have forgotten). I have moved it to an external hard drive because it was on a 4GB partition on my internal h/d which was not big enough. I had too many models installed to accommodate any more. I moved it by dragging and dropping the entire Poser folder without any problems at all. It can now grow to about 50GB before I shall need to think about getting a second bigger external drive that it can have all to itself.

I looked at Poser 5 when it was first brought out, but I don't think my system is powerful enough for it, especially my graphics card. So I stick with Poser 4 which works so well for me.