Well I've built my new box and it's sitting on the bench whilst I play with it.

After a lot of mooching around trying distros I think I'm going with Chakra. It's Arch-based, KDE, semi-rolling releases. I have it running at the moment and no surprises, glitches, or major problems. I'm currently loading it up with software I will need. If all goes well and nothing untoward leaps out I will probably bring it into full use next week sometime.