Just to report on (not much) progress, I've test-installed several distros over the last few weeks, and this comes to you from Vector Linux, which is a bit raw compared to the comfortable distros I have been using, but manageable by my brain cell. I've had to compile a couple of things from source to get them working properly, and there's some more to do. I'll probably stay with it for a while now until I get itchy feet again.
Others I've tried are:
PCLinuxOS - what I was using a month ago. Much too comfortable - everything works, no issues.
Kubuntu - almost as comfortable.
Sabayon - I was interested in this one, as it's a derivative of Gentoo, which is a 'compile everything from scratch' distro. But I couldn't get on with their forum, which uses a black theme which hurts my eyes, and no alternative theme was offered. (I've since realised that I could have switched off theming altogether in Firefox, but I didn't know that at the time.)
Gentoo - the installer crashed with an incomprehensible error message, so I've put it aside for another look in winter.
Mint - another Ubuntu derivative, with nothing really to distinguish it from Kubuntu.
Granular Linux - a derivative of PCLinuxOS, nothing much to distinguish it.