@cr0sh: A couple of people mentioned compressed air in the original "ideas" thread, but it's one of those things that I haven't got around to organising and I'm not totally convinced I'd get a lot of benefit from it. It's not too late, but I figure that I can run a hose around under the bench if I find it would be useful once the walls are closed up.
The welder circuit idea is something I arranged with the sparkie yesterday. I wouldn't run a welder in what I've been referring to as the "workshop" area, which will be a clean area for smaller work (more like a cross between an office and an electronics lab) but I want to get one soon and use it in the "dirty" workshop area at the back of the garage, so we made sure there were three separate power circuits cabled to the garage area.