OK, crunches knuckles.......
In the UK, this is a touchy subject, as our imperial system is slowly being eroded away, and it has to some become a symbol of national pride.
My preference is to use metric for smaller measurments mm, cm and even m, but for larger ones and some more traditional things such as hight i prefer feet and inches, and miles.
Americans use just pounds for wieght, we use stones (14lb) and pounds to describe wieght, though Kg is becoming more common, (spit)
So perhaps both should be used, though I'd run with imperial with a table to convert to metric.